* Morphling's high mobility allows him to easily get close to Sniper, who likes to keep his distance from enemies.

* Waveform clear Mirror Image illusions from Naga Siren. And though Ensnare can prevent Morphling from using Waveform to escape, he can easily dispel it with Manta Style, a common item on Morphling.
* Morph allows Morphling to copy Naga Siren's abilities and combine them with Manta Style, a commong item for Morphling, to destroy Naga Siren's illusions. Aghanim's Scepter upgraded Morph also allows Morphling to create a strong illusion of Naga Siren that can do the same and which can also allow Morphling to close the gap on Naga Siren.

* Clockwerk is also the least optimal target for Sniper to attack in a teamfight, although more experienced players will rarely make this mistake.
* With no mobility or disable skills, getting trapped in Power Cogs is a death sentence for Sniper.

* Heroes with long cast animations can be continuously interrupted by Battery Assault: Centaur Warrunner, Jakiro, Leshrac, Naga Siren, Underlord.

* Sniper's lack of mobility and escape mechanisms makes him one of the easier heroes for Bloodseeker to gank.

* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.

* Sniper lacks any protection against Lion's disables early in the game.
* Lion's Earth Spike and Finger of Death may roughly hit Sniper at the latter increased attack range, making it possible to gank and to disable him from afar in clashes.
* Finger of Death is incredibly dangerous for Sniper as it may shred him away from fights, or in the worst scenario, cause his death.

* Lion may upgrade Mana Drain, Hex and Finger of Death through Talent Tree and Aghanim's itens to make them affect secondary targets or turn them into AoE abilities. This can make things difficult for heroes like Phantom Lancer, Naga Siren and Terrorblade, who rely on illusion armies.

Additional:
* Both Hex and Mana Drain destroy Naga Siren's illusions in an instant, making it hard for her to teamfight or push against a team with Lion. If Lion chooses the AoE effect talent for Hex or the shard for multi-target Mana Drain, it can negate her pushing potential entirely.
* Earth Spike is an AoE disable with good damage. If used well, it can help distinguish the true Naga Siren by the damage they take (illusions take more damage).

* Headshot and Shrapnel slow is ineffective against a team with haste (which Stampede gives).
* Commonly picked up mobility items and hasted movement during his Stampede (as well as his high health pool) make him extremely hard to kill from a distance, damaging Sniper with Retaliate and Blade Mail if he has one.
* A low health pool and no escape mechanism makes him an easy target for Centaur Warrunner's burst damage and initiation (even making his team possible initiators with Stampede).

* Heroes who are reliant on illusions: Chaos Knight, Phantom Lancer, Naga Siren.

Additional:
* Centaur's Retaliate will harm all attacking enemies, which will allow Centaur Warrunner to see which is the real Naga Siren.
* A well timed Hoof Stomp followed by Double Edge will clear all Naga's illusions and prevent Naga Siren from escaping with Song of the Siren.

* Ember Spirit can close the distance between Sniper easily with his Activate Fire Remnant and further keep Sniper in place with Searing Chains.
* With the help of Aghanim's Scepter, Sniper cannot outrun Ember Spirit or chase him, even if Sniper builds mobility items.

* Heroes that heavily depend on illusions or summons, (Naga Siren, Terrorblade, Phantom Lancer, Lycan,...) are vulnerable to Sleight of Fist and even more so if Ember Spirit has Battle Fury.

* Lina defeats Sniper on the mid, because she has the same attack range as him, and her Dragon Slave ability deals much more damage to creeps, as well as to Sniper himself, than Shrapnel, which creates uncomfortable conditions for Sniper to farm on the line, which is why Lina either punches Sniper harder than he either pushes a pack of creeps up to the tower and finishes off his creeps under it, preventing Sniper from earning gold and a level.
Additional:
* Lina defeats Sniper on the mid, because she has the same attack range as him, and her Dragon Slave ability deals much more damage to creeps, as well as to Sniper himself, than Shrapnel, which creates uncomfortable conditions for Sniper to farm on the line, which is why Lina either punches Sniper harder than he either pushes a pack of creeps up to the tower and finishes off his creeps under it, preventing Sniper from earning gold and a level.

* Heroes with summons and illusions can find themselves easily bested by Lina, like Broodmother, Nature's Prophet, Chen, Terrorblade, Naga Siren, Visage, Wraith King, Lycan, Phantom Lancer, Shadow Shaman.

* Heroes with catch to disrupt Sniper's positioning and deliver him into the enemies: Batrider, Disruptor, Pudge, Vengeful Spirit.

* Many stacks of Sticky Napalm, combined with Flamebreak and Firefly, allows Batrider to destroy illusions from Mirror Image.
* If Batrider can manage to destroy all illusions from Naga Siren, he will be able to use Flaming Lasso on the real one, and will be able to drag her toward his team, potentially preventing Naga Siren from escaping with Song of the Siren.
Additional:
* Many stacks of Sticky Napalm, combined with Flamebreak and Firefly, allows Batrider to destroy illusions from Mirror Image.
* If Batrider can manage to destroy all illusions from Naga Siren, he will be able to use Flaming Lasso on the real one, and will be able to drag her toward his team, potentially preventing Naga Siren from escaping with Song of the Siren.

* Axe can easily close the distance to Sniper with Blink Dagger.
* With Berserker's Call in combination with Counter Helix and Battle Hunger, Axe can make short work of Sniper, finishing him off easily with Culling Blade due to his low HP & high attack speed in the late game.

* Axe will destroy her illusions by proccing Counter Helix more often due to him being hit by more attacks.

* Sand King is a strong ganker, allowing him to shut down squishy heroes in the early game: Phantom Assassin, Clinkz, Sniper, Enchantress.

* Since Naga Siren is a hero who barely goes for Black King Bar, she is vulnerable to nukers with strong magical damage and big area-of-effect spells in every game more than any other carry heroes: Sand King, Jakiro, Leshrac, Lina, Earthshaker, Zeus.

* Other heroes that rely on physical attacks to deal damage and not their abilities: Troll Warlord, Sniper, Monkey King, Sven.

* As long as Windranger is able to identify the real hero among the illusions, heroes relying on them can be easily tagged with Focus Fire: Chaos Knight, Terrorblade, Phantom Lancer, Naga Siren.

* Dawnbreaker can easily clear waves of Naga Siren's illusions from Mirror Image with Starbreaker, Celestial Hammer and Solar Guardian.
* Aghanim's Shard upgraded Starbreaker will allow Dawnbreaker to dispel Ensnare and freely attack Naga Siren during Song of the Siren when combined with Black King Bar, a common item on Dawnbreaker.
* Solar Guardian allows Dawnbreaker to counter any attempts of Naga Siren and rejoin her team with Solar Guardian when they require it. Aghanim's Scepter upgraded Solar Guardian can also give Dawnbreaker's allies evasion while Dawnbreaker is airborne for it's duration, as Naga Siren mainly relies on direct attacks in order to deal damage.
Additional:
* Dawnbreaker can easily clear waves of Naga Siren's illusions from Mirror Image with Starbreaker, Celestial Hammer and Solar Guardian.
* Aghanim's Shard upgraded Starbreaker will allow Dawnbreaker to dispel Ensnare and freely attack Naga Siren during Song of the Siren when combined with Black King Bar, a common item on Dawnbreaker.
* Solar Guardian allows Dawnbreaker to counter any pushing attempts of Naga Siren and rejoin her team with Solar Guardian when they require it. Aghanim's Scepter upgraded Solar Guardian can also give Dawnbreaker's allies evasion while Dawnbreaker is airborne for it's duration, as Naga Siren mainly relies on direct attacks in order to deal damage. Solar Guardian can also be used after Naga Siren uses Song of the Siren near her allies to either escape from or counter-initiate against them.

* Sniper is completely helpless against Broodmother's abilities, and can be seriously damaged by Spiderlings in lane, especially when Shrapnel is on cooldown.

* Invoker's arsenal of magical spells are troublesome for Sniper who has low HP and high armor, which does not benefit him much against Invoker.
* Besides magical damage, he can be disarmed and repeatedly mini-stunned with Cold Snap, preventing him from reacting.
* Leveling Quas can allow Invoker to lane effectively against Sniper despite right-click harassment.

* Anti-Mage can close the gap with Blink. Sniper will struggle to escape once he is jumped on due to the lack of mobility.
* Counterspell reduces sniper's magic damage from Shrapnel and Assassinate. The active component can also reflect the projectile back to sniper if he dares to target Anti-Mage. This is seriously detrimental for Sniper as he is prone to buying Khanda to boost effects of the Assassinate.
* Sniper often relies on mana to use items for escaping, and his abilities cost a lot of mana. Mana Break drains Sniper's mana and takes away Sniper's means to disengage.
* Anti-Mage has faster farming speed. He can outfarm and get ahead of Sniper easily.

* All of Leshrac's abilities, especially Pulse Nova, can easily deal with Naga Siren's illusions.
* Aghanim's Scepter gives Leshrac access to Nihilism ability, that allows him to turn himself along with Naga Siren and her illusions to turn ethereal. And to make things worse, Nihilism can slow Naga Siren and her illusions, make them more vulnerable to magical damage and unable to fight back while Leshrac moves faster and does not take increased magical damage for it's duration.

* Sniper has no spells to disable Puck. He lacks a silence to prevent spell casting and a stun to disable, allowing Puck to act instantly against Sniper.
* Sniper's main strategy is to attack his enemies from a safe distance. Illusory Orb, combined with Blink Dagger makes it easy for Puck to get close to Sniper. Due to his low health, he is also easily nuked down by Puck.
* The status debuff placed by Assassinate on its target makes it very easy to avoid it. Puck has 2 (3 when having Blink Dagger, 4 when having Eul's Scepter of Divinity, 5 when having Linken's Sphere) methods to disjoint or dodge the projectile, making it a bad spell for finishing off Puck.

* Shadow Step and Haunt from Aghanim's Scepter instantly allows Spectre to get up and close with Sniper, and Spectral Dagger makes it difficult for Sniper to escape from her.
Additional:
* Spectre can reach him easily in the backlines with Spectral Dagger or teleport to him with Haunt.
* He is usually a fair distance away from his allies, so Desolate will quickly tear Sniper down.
* Dispersion reflect or reduce his damage, making her hard to take down even at late game.

* Spirit Breaker can charge towards Sniper from anywhere on the map with Charge of Darkness.
* Greater Bash deals magical damage, which can prove dangerous to Sniper and his low health.
* Both previous abilities combined with Nether Strike ensures that Spirit Breaker can easily solo kill Sniper.

* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.

* Zeus's abilities deal high amounts of burst magical damage, which ignores Naga Siren's high armor.
* Arc Lightning is a good way to destroy Naga Siren's illusions due to it's capabilities to bounce between enemies.
* Static Field from Aghanim's Shard can automatically hit everything in a big radius, taking a huge chunk of health out of Naga Siren's illusions, regardless of how much health they have.

* Flak Cannon and Call Down can easily clear Naga Siren's illusions.

* Sniper has a low health pool and strength gain, making him vulnerable to Pudge's magical and pure damage.
* Sniper usually likes to deal damage away from the fight, and Meat Hook is capable of bringing him to the front lines.
* Assassinate won't do much damage against Pudge because of his high strength gain and the strength bonuses from Flesh Heap.
* Shrapnel will be mostly blocked by Flesh Heap's active.
Additional:
* Pudge's Meat Hook allows him to bring Sniper in the middle of any fight, and the pure damage does well against his high armor and low health.
* Dismember can lock Sniper down, which makes him highly vulnerable and gives enough time for Pudge to kill him alone. Aghanim's Shard upgraded Dismember will also allow Pudge to save an ally from Assassinate.

* Shukuchi allows Weaver to close the gap between himself and Sniper with high speed, and to maneuver through teamfights to get on top of him.
* A combination of The Swarm and Desolator tears through Sniper's low armor.

* Snowball allows Tusk to move himself and allies towards Sniper whilst invulnerable and hidden.
* His Ice Shards may also block pathing for Sniper as he has no means of moving through obstacles. In addition, Tag Team can hinder Sniper's escape.
Additional:
* Tusk alone or with his teammates can close Sniper's long range easily with Snowball, even wasting Shrapnel, ending with a very vulnerable Sniper.
* Walrus PUNCH!'s very high physical damage output can easily kill Sniper instantly due to his low health and armor.

* Past the early game, Sniper is an easy target for Sven to jump on with Aghanim's Scepter upgraded Storm Hammer, Blink Dagger, Silver Edge or Harpoon, common items on Sven.
* Sven's high armor and health pool makes it difficult for Sniper to focus, as his main source of damage is his right click, especially if Sven uses Warcry.
* Sniper is very squishy, and will not stand a chance against Sven head on.

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Mortimer Kisses can make quick work of Naga Siren's illusions.
* Scatterblast and Firesnap Cookie's AoE damage are also decent ways to deal with Naga's illusions.

* Even if he can slow Mars down with Shrapnel and Headshot, Mars can tank Sniper's physical damage simply by facing him with Bulwark, allowing him to endure his auto-attacks into the late-game. Should Sniper choose to attack someone else, Mars can redirect his projectiles with Bulwark's active ability.
* Sniper's poor mobility makes him very vulnerable to Arena of Blood, especially in the early game. Mars can also take advantage of this by pushing him closer to the front line with Spear of Mars.

* Sniper's Take Aim can be wasted with either Muerta's Pierce the Veil or a well aimed Dead Shot.
* Dead Shot can displace Sniper from safe spots into the offensive range of Muerta's team, leading to potential kills on Sniper.
* Sniper relies heavily on his basic attacks, which is useless against Pierce the Veil.

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Timbersaw's innate durability provided by Reactive Armor is very hard to deal with as Naga Siren as she mostly relies on sustained damage rather than burst damage unless if she is played as Nuker.
* Timbersaw's high pure damage and low-cooldown area-of-effect nukes which are Whirling Death, Timber Chain, Chakram and Flamethrower from Aghanim's Shard can also destroy Naga Siren's illusions very fast.
* Timbersaw is a common Lotus Orb wielder which allows him to reflect Ensnare back at Naga SIren.

* Naga Siren's Song of the Siren may be useful but Poof will destroy all of her illusions.

* Heroes with AoE nukes will clear her illusions in no time, especially if they are percentage-damage-based, like Underlord's Firestorm, Elder Titan's Earth Splitter, Enigma's Midnight Pulse, Zeus's Arc Lightning, Jakiro's Liquid Frost from Aghanim's Shard etc.

* Fortune's End can catch out or impair position-based heroes with low mobility, such as Sniper or Razor.

* Heroes with catch to disrupt Sniper's positioning and deliver him into the enemies: Batrider, Disruptor, Pudge, Vengeful Spirit.

* Sniper's low mobility and lack of defensive abilities make him an easy gank target for the entire game, especially if Blink Dagger is picked up.

* Heroes who rely on illusions will see them destroyed easily by Overwhelming Odds: Phantom Lancer, Chaos Knight, Terrorblade, Naga Siren

* Early game gankers can make life very difficult for a Sniper if he keeps being caught: Ursa, Pudge, Earth Spirit.

* Heroes with high mobility can approach Sniper: Anti-Mage, Earth Spirit, Io, Nature's Prophet, Pangolier, Puck, Queen of Pain and most notably Riki.

* Invisible heroes all have the element of surprise. Provided they deal enough damage, Sniper should be vanquished very quickly: Clinkz, Riki, Bounty Hunter.

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Keeper of the Light can stall pushes with Illuminate. This makes him strong against pushing heroes: Terrorblade Naga siren Nature's Prophet and Anti-Mage

* Clinkz, Sniper, Lone Druid, Troll Warlord, Legion Commander and Wraith King are some of the Heroes that base themselves on attacks with little or no spell power, so they suffer in the grassy hands of Overgrowth.

* Heroes with high mobility can approach Sniper: Anti-Mage, Earth Spirit, Io, Nature's Prophet, Pangolier, Puck, Queen of Pain and most notably Riki.

* Heroes with high physical damage output but lack of reliable escape mechanisms are always a good target for a solo gank: Sniper, Shadow Fiend, Troll Warlord, Drow Ranger. Those heroes, however, are dangerous if they manage to close the gap, so take caution.

* Heroes who have high health are a problem for Sniper because he likes to attack the closest target and sit at the back, much like a Terrorblade so when that hero doesn't die; he's forced to show his position for a very long time: Centaur Warrunner, Legion Commander, Primal Beast.

* Carry heroes who can close the gap reliably are very problematic: Phantom Lancer, Ember Spirit, Phantom Assassin.

* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - Sniper, Drow Ranger, Lina, Rubick, etc.

* Range-reliant heroes: Sniper, Drow Ranger

* Lifestealer can close the distance to Sniper by using Infest on a fast or durable creep to tank Sniper's damage.
* Open Wounds and Ghoul Frenzy will reduce Sniper's mobility heavily, and Rage's movement speed bonus helps in closing the gap to Sniper. It also protects him from Assassinate and Shrapnel.
* Infest can dodge an incoming Assassinate or to surprise Sniper during ganks. Aghanim's Scepter upgraded Infest can also allow Lifestealer to disarm Sniper and attack him from inside.

* Tinker is one of the few heroes who is able to defeat a Sniper on the center line thanks to his long-ranged abilities.
* Laser allow Tinker to deal damage to Sniper and blind him, causing him to miss attacks more often.
* Heat-Seeking Missile can deal heavy damage to Sniper on lane.
* Defense Matrix allow Tinker to save himself or allies from Assassinate.
* Warp Flare from Aghanim's Shard allows Tinker to teleport Sniper away from himself, while also reducing both his attack range and cast range. If Sniper is teleported near Tinker's allies with Warp Flare, he will be bursted down in no time.
Additional:
* Tinker is one of the few characters in Dota 2 who is able to defeat a Sniper on the center line – Tinker. On the center line, he gains an advantage over his opponent, and later acquires additional control. It is these abilities that the enemy should have in the game against the Sniper.

* Slardar can use Guardian Sprint with Blink Dagger or Shadow Blade to get close, and Slithereen Crush will stun Sniper and slow him, making him vulnerable to Slardar's teammates.
* Corrosive Haze lowers Sniper's armor and makes Sniper's Shadow Blade useless, easily killing him with a few attacks.

* Sniper relies on distance. Bounty Hunter can use Shadow Walk to get close, and Jinada can do massive damage and slow down Sniper in the early game.
* Track gives additional speed to Bounty Hunter and makes Shadow Blade useless, which can allow Bounty Hunter to easily kill him with a few attacks.

* Assassinate is easy to reflect with Spiked Carapace for massive damage.
* Shrapnel's area damage can set up an easy stun with Spiked Carapace, especially when combined with Vendetta.
* In the early game, Sniper's low health pool and high intelligence makes him easy prey for Nyx Assassin.

* Sniper hugely lacks mobility and escape abilities so that he is an easy target for ganks from Slark.

* Jakiro's damage over time abilities can clear Naga Siren's illusions and can hurt real Naga Siren even for the duration of Song of the Siren.
* Naga Siren is not a hero that likes to go for Black King Bar, and that makes her very vulnerable to Jakiro's damage over time in every phase of the game.
Additional:
* Jakiro's damage over time abilities can clear Naga Siren's illusions and can hurt real Naga Siren even for the duration of Song of the Siren.
* Since Naga Siren is a hero who barely goes for Black King Bar, this can make her very vulnerable to Jakiro's damage over time in every phase of the game.

* Sniper has no natural escape and relies on his range and slows to keep himself safe, which Riki can bypass with Blink Strike and quickly deplete his miniature HP pool.

* Sniper is very fragile and has low movement speed, making an exceptionally easy target for Chaos Knight to initiate on.
* Sniper has no innate ability to deal with Phantasm or escape a Reality Rift and Chaos Bolt combo.
* In most cases, Sniper likes to stay far in the backline to deal damage, thus he is vulnerable if Chaos Knight manages to jump on him in the back line, which will usually spell a quick end for Sniper.

* Storm Spirit can close the distance towards Sniper very easily with his ultimate Ball Lightning.
Additional:
* Sniper is very squishy and cannot deal with heroes that jump onto him and lock him down. Storm Spirit closes the gap in a fight against Sniper, and Sniper has no way to escape except for some items.
* Storm Spirit can dodge Assassinate with a correctly timed Ball Lightning.

* Avalanche and Toss combo makes short work of Mirror Image's illusions.
* Tiny's cleave with Tree Grab and area of effect damage with Tree Volley will easily wipe out illusions.

* Pangolier can easily get close to Sniper with Swashbuckle and Rolling Thunder, negating Sniper's range advantage.
* Lucky Shot disarms Sniper and leaves him unable to effectively fight back.

* Heroes who are illusion based, or even heroes who frequently build Manta Style can be cleared quickly by Pangolier's high damage, or lose their damage ouput because of Lucky Shot: Chaos Knight, Naga Siren

* Sniper's lack of mobility and reliance on attack range makes him an easy target for Phantom Assassin to jump on.
Additional:
* Stifling Dagger and Phantom Strike allow Phantom Assassin to close the gap with Sniper and prevent his escape.
* Blur allows Phantom Assassin to approach Sniper while invisible and dodge much of Sniper's damage. It can also disjoint Assassinate.
* Coup De Grace quickly cuts through Sniper's low health; one or two procs will usually kill him.
* Fan of Knives from Aghanim's Shard can deal damage to Sniper's maximum health and disable Headshot and Take Aim.

* Heroes with high mobility can approach Sniper: Anti-Mage, Earth Spirit, Io, Nature's Prophet, Pangolier, Puck, Queen of Pain and most notably Riki.

* Heroes who have high health are a problem for Sniper because he likes to attack the closest target and sit at the back, much like a Terrorblade so when that hero doesn't die; he's forced to show his position for a very long time: Centaur Warrunner, Legion Commander, Primal Beast.

Additional:
* Sunder can save himself or his allies from Assassinate.
* Sniper relies on right-clicks to deal damage in the late game, and Terrorblade's high armor can reduce his damage significantly.
* Terrorblade is a far harder carry than Sniper is, so a well-farmed Terrorblade can easily defeat a Sniper.

* Heroes with catch to disrupt Sniper's positioning and deliver him into the enemies: Batrider, Disruptor, Pudge, Vengeful Spirit.

* Heroes with powerful nuke can waste their precious abilites on her Refraction during a ganking attempt or chaos combat: Lich, Lina, Sniper, Outworld Destroyer Zeus

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Frail heroes who lack mobility can also be an easy target to lock down with Chronosphere, such as Drow Ranger, Luna, Sniper, Terrorblade.

* Medusa's Split Shot and Mystic Snake combined with Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.
Additional:
* Medusa's Split Shot and Mystic Snake combined with Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.

* Blade Fury offers good AoE damage to clear illusions and can hurt the real Naga Siren as well if she chooses to blend in the illusions. Diffusal Blade does nothing to Juggernaut either when he uses Blade Fury.
* Aghanim's Shard upgraded Blade Fury along with Lv 20 DPS talent will shred all illusions almost instantly, especially when combined with Mjollnir, a common item for Juggernaut.

* Heroes with high mobility can approach Sniper: Anti-Mage, Earth Spirit, Io, Nature's Prophet, Pangolier, Puck, Queen of Pain and most notably Riki.

* Squishy core heroes (Shadow Fiend, Sniper, etc)

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Heroes who are reliant on illusions or summons: Chaos Knight, Broodmother, Naga Siren.

* You can easily kill a squishy Sniper, due to your high movement speed and his lack of escape.

* Sand King and Phoenix have many tools to deal with multiple enemies at once, which will work well against a crowd of illusions.

* Heroes with AoE nukes will clear her illusions in no time, especially if they are percentage-damage-based, like Underlord's Firestorm, Elder Titan's Earth Splitter, Enigma's Midnight Pulse, Zeus's Arc Lightning, Jakiro's Liquid Frost from Aghanim's Shard etc.

* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: Phantom Lancer, Chaos Knight, Naga Siren, Terrorblade.

* Luna's Moon Glaives and Lunar Blessing can clear waves of Naga Siren's illusions from Mirror Image.
* Once Naga Siren's illusions are cleared with Aghanim's Shard upgraded Moon Glaives, Eclipse can often finish off Naga Siren before she can escape with Song of the Siren.
* A well-timed Aghanim's Scepter upgraded Eclipse combined with 0.25 Eclipse Lucent Ministun talent can be casted at long range and allow Luna to burst down Naga Siren faster and repetively stun Naga Siren, preventing her from escaping with Song of the Siren and Town Portal Scroll without getting caught in it's range.
* Luna is a natural Black King Bar wielder unlike Naga Siren who barely goes for it, which allows Luna to freely attack Naga Siren during Song of the Siren and potentially get rid of the most of the damage and crowd-control from Naga Siren.
Additional:
* Luna's Moon Glaives and Lunar Blessing can clear waves of Naga Siren's illusions from Mirror Image, especially when combined with Gleipnir and Manta Style. Aghanim's Shard upgraded Moon Glaives can also be used to destroy Naga Siren's illusions and damage the real Naga Siren if they are too close to Luna while also reducing any damage Naga Siren inflicts on Luna for their duration.
* Once Naga Siren's illusions are cleared, Eclipse can often finish off Naga Siren before she can escape with Song of the Siren.
* A well-timed Aghanim's Scepter upgraded Eclipse combined with 0.25 Eclipse Lucent Ministun talent can be casted at long range and allow Luna to burst down Naga Siren faster and repetively stun Naga Siren, preventing her from escaping with Song of the Siren and Town Portal Scroll without getting caught in it's range.
* Luna is a natural Black King Bar wielder unlike Naga Siren who barely goes for it, which allows Luna to freely attack Naga Siren during Song of the Siren and potentially get rid of the most of the damage and crowd-control from Naga Siren.

* Atrophy Aura makes it hard or Naga Siren to farm on lane and damage Underlord with Rip Tide in teamfights. And her only way to counter this is by playing Nuker role.
* Firestorm is very useful for clearing Naga Siren's illusions from Mirror Image and Manta Style.
* However, Naga Siren can catch Underlord and his team unprepared with Song of the Siren if he chooses to use Fiend's Gate to get to a designated point of the map. Naga Siren can also prevent escaping with Fiend's Gate with Ensnare and Reel In from Aghanim's Scepter.
Additional:
* Atrophy Aura makes it hard or Naga Siren to farm on lane and damage Underlord with Rip Tide in teamfights. And her only way to counter this is by playing Nuker role.
* Firestorm is very useful for clearing Naga Siren's illusions from Mirror Image and Manta Style.
* However, Naga Siren can catch Underlord and his team unprepared with Song of the Siren if he chooses to use Fiend's Gate to get to a designated point of the map. Naga Siren can also prevent escaping with Fiend's Gate with Ensnare and Reel In from Aghanim's Scepter.

* Viper Strike breaks Sniper's passives.
* Corrosive Skin allows Viper to deal more damage to Sniper than Sniper deals to him when laning, especially by briefly stepping into Shrapnel.
* Nethertoxin together with Poison Attack can slow Sniper and tears through his low health and mobility.

* In the mid to late game, the physical attack from Sniper can be painful to go through as Rubick. However with the help of Rubick's teammates, the abilities of Sniper can turn against his team.
* Shrapnel is a great wave-clear ability, and helps with scouting the area.
* Shrapnel already has a long cast range, and together with Arcane Supremacy Rubick can put constant damage on Sniper while he stays at back.
* Assassinate, if stolen, can be cast to assist a gank while Rubick stays at a range that can merely be found in the area, damaging heroes in the backline including Sniper.
* Arcane Supremacy (combined with Level 25 talent +40% Spell Amp For Stolen Spells, as of 7.31c) increases its damage before reduction to 406.2/611.1/819(531.2/805.1/1079) without considering any further amplification source.
* With Aghanim's Scepter, Assassinate becomes an ability with a reliable 1.5 second stun, massive damage, short cooldown and over 3000 cast range which should not be made light of.
* Shrapnel is used frequently and can be easily stolen; Assassinate has a long cast animation for Rubick to forsee the chance to steal.

* Magnetic Field's evasion completely negates Sniper's attacks unless he has True Strike.
* Sniper always positions himself far away from battles, which makes him especially vulnerable for Flux and Spark Wraith.

* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.

* Being mostly a physical damage dealer, Sniper's effectiveness is greatly reduced by Omniknight's Guardian Angel.
* Omniknight's Degen Aura allows him to slow sniper and catch him. Sniper has to then use some escape item.
* Omniknight can also protect an ally from being finished off by Assassinate by using Purification and Repel which grants a massive strength boost.

* Low-health, normally mobile carries who rely entirely on raw attack damage are vulnerable to Bane's nukes and disables: Anti-Mage, Clinkz, Drow Ranger, Faceless Void, Gyrocopter, Juggernaut, Meepo, Mirana, Monkey King, Morphling, Phantom Assassin, Phantom Lancer, Riki, Shadow Fiend, Slark, Sniper, Terrorblade, Troll Warlord, Weaver.

* Mirror Image's illusions increase Echo Slam's damage.
Additional:
* Earthshaker's strong AoE abilities can clear Naga Siren's illusions, or at least make it easier to distinguish the real one by the damage they take.
* Echo Slam deals more damage against more enemies, which can be devestating against Naga Siren and her illusions.

* Dazzle can instantly destroy all of Naga Siren's illusions from Mirror Image with Aghanim's Shard upgraded Poison Touch used on her or any of her illusions.

* Arcane Orb allows Outworld Destroyer's attacks to deal pure damage that can bypass Naga Siren's armor, and which can clear her illusions in no time.
* Astral Imprisonment can be used to harass Naga Siren by reducing her maximum mana and to prevent Naga Siren from escaping with Song of the Siren. Outworld Destroyer can also use Astral Imprisonment to protect himself from Naga Siren.
* Sanity's Eclipse will most likely instantly kill Naga Siren along with her illusions. Even if Naga Siren survives Sanity's Eclipse, it's mana allergy debuff will discourage Naga Siren from using her abilities as the mana allergy will heal Outworld Destroyer if she uses them for it's duration.