Undying
* 
Tombstone's zombies rarely inhibit Anti-Mage, as he can either Blink away or onto the Tombstone and destroy it.
Bristleback
* Mana Break quickly eats away at Bristleback's small mana pool, preventing him from spamming 
Viscous Nasal Goo and 
Quill Sprays.
* Bristleback has no innate mobility. Bristleback is easily kited by Blink, ignoring the protection from 
Bristleback.
Additional:
* 
Mana Break removes both a percentage and flat amount of your mana, preventing Bristleback from using abilities in the lane.
* 
Blink Anti-Mage has very high mobility with this skill, and can easily escape from Bristleback since he has no way to prevent his blink. He can also use this offensively to get in front of Bristleback during fights.
Undying
* Geminate Attack works on Tombstone, allowing Weaver to kill it quickly.
* Zombies attacking Weaver disappear once he goes invisible with Shukuchi.
* Undying has no way to catch a mobile Weaver.
Bristleback
* 
Shukuchi gets Weaver in front of Bristleback, negating the protection from Bristleback.
* Weaver's mana break talent depletes Bristleback's mana pool, preventing him from spamming abilities.
Undying
* 
Reactive Armor makes Timbersaw very effective against heroes that control a lot of units, such as 
Broodmother, 
Lycan and 
Undying.
Bristleback
* 
Whirling Death deals damage while also reducing {Show:A|Timbersaw|Whirling Death|value4} of Bristleback's strength, making him less tanky.
* Reactive Armor can sustain through multiple Viscous Nasal Goo and Quill Spray stacks.
* 
Timber Chain makes it hard for Bristleback to slow down Timbersaw even with Viscous Nasal Goo.
Undying
* Necrophos is a dangerous opponent to go against with. Regardless of how much strength Undying has gained from Decay, Necrophos can finish off Undying with 
Reaper's Scythe once Undying's HP falls below a certain threshold.
* 
Heartstopper Aura will do more damage to Undying if he gained strength from Decay, as it does damage based on a hero's maximum health.
Bristleback
* Reaper's Scythe and Heartstopper Aura deal percentage-based damage, ignoring Bristleback's high health.
* Heartstopper Aura's HP removal does not trigger Bristleback's passive.
Additional:
* Heartstopper Aura deals percentage-based damage flagged as HP removal, so it is not reduced by Bristleback, nor does it trigger passive Quill Sprays.
* Reaper's Scythe is very effective against Bristleback not only due to its percentage-based damage, but rather because it first stuns and then deals its damage, allowing Necrophos to position in front of Bristleback in time.
Bristleback
* Enemies that possess high defenses through magic resistance, damage reduction, or high regeneration will make it difficult to whittle their health down to get to Reaper's Scythe's threshold. Such heroes include 
Bristleback (although only from behind), 
Spectre, 
Ursa, and 
Dragon Knight.
Undying
* 
Terrorblade can destroy Tombstone with his 
Conjure Image and 
Metamorphosis.
Bristleback
* Terrorblade's 
Sunder is not affected by the Bristleback damage reduction.
Bristleback
* Outworld Destroyer's high burst damage is not negated by Bristleback's passive. So, even if Bristleback turns his back on Outworld, he can decimate Bristleback quickly.
* If Bristleback attempts to flee, or tries to close the gap, Outworld can banish him with 
Astral Imprisonment, both reducing Bristlebacks much needed mana and allowing Outworld to move in front of him, forcing him to take the full damage from his spells. This will also allow Outworld to land a devasting Sanity's Eclipse, without it being reduced by Bristleback's passive.
Undying
* Zombies summoned from Tombstone will amplify the damage of 
Echo Slam due to them increasing the echo damage.
Undying
* Tidehunter takes close to no damage from Undying's zombies once he maxes out his 
Kraken Shell, especially if he gets the level 20 Kraken Shell upgrading talent. This might allow him to blink away to safety.
Bristleback
* 
Duel makes Bristleback fight Legion Commander face to face, forcing him to take full damage.
* 
Press the Attack dispels the slow from stacks of Viscous Nasal Goo.
Additional:
* When dueled, Bristleback will have to face Legion head on, not allowing his passive Bristleback to come into effect.
Bristleback
* 
Guardian Sprint allows Slardar to outrun Bristleback, even when slowed by Viscous Nasal Goo.
* 
Corrosive Haze's armor reduction makes Bristleback much less tanky.
Undying
* Chemical Rage will take down Tombstone in no time.
Additional:
* With 
Greevil's Greed, Alchemist can farm Tombstone zombies and gain a significant gold advantage.
Undying
* Flak Cannon rips through Tombstone's zombies.
Additional:
* 
Flak Cannon enables Gyrocopter to clear the zombies easily.
Bristleback
* 
Essence Shift allows Slark to hit Bristleback freely whether on the front or back, stealing attributes and make Bristleback much less tanky.
* 
Pounce can be used to disengage and recover lost HP with his ultimate passive, and can return to fight in a short period while Bristleback is already injured and got some of his attributes stolen.
* 
Dark Pact makes it near impossible to keep the Viscous Nasal Goo debuff on Slark.
* Although Dark Pact cannot dispel Quill Spray, meaning that Slark will still receive quill stack damage even if he used 
Shadow Dance before.
* Slark builds 
Silver Edge in almost every game, an item that greatly counters Bristleback.
Bristleback
* 
Phantom's Embrace silences Viscous Nasal Goo and Quill Spray.
* 
Ink Swell stuns Bristleback and gets allies in position faster with increased movement speed to attack his front, countering his passive ability.
Bristleback
* 
Time Dilation prevents Bristleback from spamming his low-cooldown abilities, greatly reducing his damage and effectiveness.
* 
Chronosphere allows allies to reposition and hit Bristleback from the front, bypassing his defensive bonus from behind.
* Bristleback has no way to prevent Void from using 
Time Walk.
Additional:
* Time Dilation while Quill Spray and Viscous Nasal Goo are on cooldown will make these abilities unusable for a long time, rendering Bristleback nearly useless.
* Bristleback cannot turn inside the Chronosphere, which makes it easy to attack him from the front, completely bypassing his passive damage reduction.
Undying
* Sniper can easily destroy Tombstone from long range.
Undying
* Due to Fervor and Battle Trance, Troll Warlord has a significant attack speed, enabling him to crush Tombstone quickly.
* Undying usually stays at the front line with no disables, making him an easy target for Troll Warlord.
Bristleback
* 
Eye of the Storm melts Bristleback's armor, and makes him much less tanky.
* 
Static Link can completely drain Bristleback's bonus damage from Warpath.
* 
Storm Surge allows Razor to outdistance Bristleback, even with a few stacks of Viscous Nasal Goo on him. Also, if Razor has his Shard, it will deal full damage to Bristleback every time he uses Viscous Nasal Goo (as Bristleback will face him to cast it).
Additional:
* Eye of the Storm melts Bristleback's armor, and makes him much less tanky.
* Static Link can completely drain Bristleback's bonus damage from 
Warpath.
Bristleback
* 
Nethertoxin disables Bristleback's passive.
* 
Viper Strike and 
Poison Attack slow down Bristleback's movement speed, making him unable to get out from Nethertoxin.
Additional:
* Viper Strike can disable Bristleback and prevents Warpath from building stacks. Besides losing his defensive passive, Bristleback also loses his ability to build up damage over lengthy battles.
* Viper can perpetually kite Bristleback with Poison Attack and Viper Strike.
Bristleback
* 
Sharpshooter deals massive damage to Bristleback and applies a high duration disable on his passive.
* 
Bushwhack and 
Scurry can be used to easily kite Bristleback.
Additional:
* Bristleback and Warpath can be disabled by Hoodwink's Sharpshooter ability for a long period of time, reducing his both offense and defense.
* Scurry and Bushwhack can be used to kite bristleback.
Undying
* Familiars will easily be able to kite heroes with a short range or with low attack speed. For example, 
Tiny and Undying have a very hard time killing Familiars.
Bristleback
* Heroes that withstand damage like 
Timbersaw, Bristleback, Dragon Knight and others will have their durability largely reduced when hit by an Ice Blast due to the risk of shattering.
Undying
* 
Mirana can destroy Tombstone, and evade zombies using Leap and Moonlight Shadow's invisibility.
Undying
* 
Invoker's multiple spells can lock down Undying and disable him from doing much.
Bristleback
* Heroes with high health especially Strength heroes will take more damage on Sun Ray: 
Axe, 
Pudge, Bristleback, 
Mars.
Bristleback
* 
Lion's 
Mana Drain is a headache for Bristleback to deal with during the laning stage, as it denies him the ability to get last hits with Quill Spray.
Undying
* 
Death Prophet is able to 
Silence Undying up to 6 seconds. Besides, due to Undying's high strength during a team fight, 
Spirit Siphon is a powerful ability against Undying thanks to the percentage health drain.
Undying
* Heroes without blink mechanisms or spell immunity will have a hard time positioning against 
Pit of Malice: 
Sven, Tiny, 
Wraith King, Dragon Knight, 
Meepo, 
Doom, 
Bounty Hunter, 
Dark Seer, Undying, 
Alchemist, 
Legion Commander.
Bristleback
* 
Shadow Demon's 
Demonic Purge with 
Aghanim's Scepter disables Bristleback's passives.
Undying
* Heroes with summons that are destroyed by a fixed number of attacks: Undying's Tombstone, 
Gyrocopter's 
Homing Missile, and 
Zeus's 
Nimbus.
Bristleback
* 
Batrider's turn rate slow from 
Sticky Napalm makes it harder for Bristleback to keep his back towards the enemy.
Undying
* Lifestealer is able to endure Undying, especially in the laning phase, where Undying is strongest. Feast can offset 
Decay's strength steal for its percentage lifesteal. Rage delays Undying from stealing strength and can help Lifestealer destroy Undying's Tombstone uninterrupted. As well, none of Undying's abilities pierce magic immunity.
Bristleback
* Heroes with high physical damage can damage Lifestealer more than he can heal: Bristleback, 
Clinkz, 
Luna,
Shadow Fiend, 
Slardar, Terrorblade
Undying
* Split Shot can destroy Tombstone Zombies and Tombstone itself while still damaging heroes.
Bristleback
* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: 
Tidehunter, Bristleback, Slardar.
Undying
* Luna's 
Moon Glaives and 
Lunar Blessing can help her destroy Tombstone easily, and this becomes more effective if Luna is equipped with 
Manta Style.
* Spell Immunity of Zombies from Tombstone is a total disadvantage against Luna because 
Eclipse will strike only Undying, which can turn Undying's own ability against him.
* Though Undying often builds 
Blade Mail which can turn Luna's burst damage against her, Luna often builds 
Black King Bar which will allow her to attack Undying freely because Blade Mail cannot pierce spell immunity.
Additional:
* Luna's Moon Glaives and Lunar Blessing can help her destroy Tombstone easily, and this becomes more effective if Luna is equipped with Manta Style.
* Spell Immunity of Zombies from Tombstone is a total disadvantage against Luna because Eclipse will strike only Undying, which can turn Undying's own ability against him.
* Though Undying often builds Blade Mail which can turn Luna's burst damage against her, Luna often builds Black King Bar which will allow her to attack Undying freely because Blade Mail cannot pierce spell immunity.
Bristleback
* Heroes with damage-over-time abilities easily allow Bristleback to turn his back in order to proc Bristleback continuously and to massively reduce to damage dealt to him: 
Arc Warden, 
Venomancer, Luna.
Additional:
* Quill Spray and Bristleback harass Luna more efficiently than she does with Lucent Beam.
* Bristleback helps return a lot of damage to Luna’s team if she uses her nukes on him and he has his back to her, and her only way to counter this is by buying Silver Edge.
* Viscous Nasal Goo and Warpath are enough to outrun a speedy Luna.
* Bristleback tends to be a frequent carrier of 
Crimson Guard and 
Eternal Shroud, which are good protection from Moon Glaives and Eclipse.
* For the same reasons, Bristleback makes a very powerful ally for Luna when they are in the same team.
Bristleback
* 
Infernal Blade deals scaling damage and is useful against high health targets such as Bristleback.
* 
Doom disables Bristleback's low cooldown abilities, preventing him from triggering Warpath. With his upgraded level 25 talent, it also breaks Bristleback's passive, rendering him more vulnerable.
Additional:
* Infernal Blade deals scaling damage and is useful against high HP targets such as Bristleback.
* Doom prevents Bristleback from casting his two low cooldown abilities, which then prevents him from utilizing Warpath.
* If Doom chooses the Level 25 talent {ValueColor:1|Doom applies Break|25tal} {Symbol:Talent}, he can disable Bristleback and Warpath, taking away much of his durability and damage potential in team fights.
Undying
* Heroes with a slow attack rate will find themselves struggling to take out Tombstone, like Doom.
Undying
* Undying's Tombstone will cheerfully chew through treants, incidentally netting you some extra income during fights.
* The above interaction tends to ensure that skirmishes are heavily populated with units, thereby buffing 
Soul Rip
Bristleback
* Heroes that have AoE damage: 
Lina, 
Keeper of the Light, Timbersaw, 
Leshrac, Bristleback, Axe.
Undying
* Generally, any fragile heroes will have a hard time dealing with Undying's tankiness, and even more so if Decay is used on them. Some examples are 
Crystal Maiden and 
Witch Doctor.
Bristleback
* Viscous Nasal Goo can hinder Crystal Maiden's already abysmal mobility, which allows Bristleback (or his teammates) to run her down and kill her.
* Bristleback frequently builds Blade Mail, which can quickly kill Crystal Maiden if her ultimate is used while he is under its effect.
* The passive part of Bristleback will trigger many, many times under the damage from Freezing Field, and as the stacks increase, the damage output from each successive cast (or proc) will eat away at Crystal Maiden's small HP pool.
Undying
* Anti-Tank heroes like: 
Razor, 
Necrophos, Undying.
Bristleback
* Bristleback is one of the hardest heroes to gank with a 
Meat Hook and 
Dismember combo, and attempts to do so sometimes backfire on Pudge.
Additional:
* Pudge is particularly susceptible to Bristleback's Viscous Nasal Goo and Quill Spray due to his naturally low armor and poor agility gain.
* Bristleback, in combination with his strength gain, high health, common itemization for magic resistance and damage reduction from Bristleback makes him a poor target for Pudge.
Bristleback
* Combo Quill Spray and items Blade Mail can easily trigger from Focus Fire damage.
Additional:
* Using Focus Fire on Bristleback tends to fare badly for Windranger, as he can trigger passive Quill Sprays many times, especially when she attacks him from behind. In addition, Windrun does not protect her from both Viscous Nasal Goo and Quill Spray, rendering her helpless.
* Bristleback's natural tankiness makes it hard for Windranger to effectively burst her down throughout the game.
* Bristleback tends to continuously spam Viscous Nasal Goo to slow down Windranger when she uses Windrun to escape, potentially allowing him to outrun her with his Warpath stacks.
* Bristleback can build 
Lotus Orb to reflect Shackleshot and Focus Fire back at Windranger.
Bristleback
* Tiny's nonexistent armor in the early game makes him very vulnerable to Quill Spray's large amounts of physical damage.
* Bristleback decreases Tiny's high burst damage against Bristleback.
* Viscous Nasal Goo can slow Tiny to a crawl and allows Bristleback to easily kite him with his high movement speed and Quill Spray's long range, as Tiny has no ability to escape.
Undying
* Decay, Soul Rip and 
Flesh Golem all deal magical damage which ignores Bulwark.
* Decay reduces Mars' natural strength and therefore his health pool, which is what he relies on to trade effectively in lane.
Undying
* Undying can use Decay not only to reduce Sven's maximum health, but also to reduce the damage he can deal with his ultimate.
* Zombies spawned by Tombstone together with Flesh Golem slow Sven down significantly. Landing Sven's powerful but somewhat slow right-click on Tombstone would be a waste.
Bristleback
* Quill Spray will hit Sand King inside 
Sand Storm, damaging him and putting Sand King's 
Blink Dagger on cooldown, preventing him from escaping.
* 
Epicenter's numerous damage ticks will trigger Bristleback's passive repeatedly during teamfights.
Bristleback
* Arc Warden has relatively lower armor and mobility, which makes him an easy target to apply Quill Spray and Viscous Nasal Goo stacks.
* Arc Warden also does not like to build a Silver Edge as it takes a long time to build up and may slow down the timings for other important items needed in the game like 
Gleipnir.
* However, do note that in a game where Arc Warden's team has many jumping capabilities or good passives, like a Tidehunter or Spectre, a Silver Edge becomes incredibly valuable on Arc Warden as not only can he run away from the jumps, he effectively gets 2 breaks, and Bristleback may not be the best pick.
Bristleback
* Quill Spray will hit Riki even when he is invisible.
* 
Cloak and Dagger's bonus backstab damage is rendered irrelevant against Bristleback.
* 
Smoke Screen does not stop Bristleback's passive from activating.
* Due to Bristleback's natural tankiness, he is an ideal 
Gem of True Sight carrier, directly countering Riki's invisibility.
Additional:
* The bonus Backstab damage from Cloak and Dagger is rendered irrelevant with Bristleback and hurts Riki more than him because of the passive Quill Spray.
* Riki can still get damaged by Bristleback's Quill Spray while invisible, and it can be hard to deal with in lane.
* Bristleback is not too bothered by Smoke Screen. Though he cannot use Quill Spray manually inside it, it still procs passively when he takes damage from the back. The movement speed from Warpath allows him to get out of the area easily.
* Due to Bristleback's natural tankiness, he is an ideal Gem of True Sight carrier.
* Riki rarely buys Silver Edge to break Bristleback's passive because the invisibility aspect of it is redundant.
Bristleback
* Quill Spray's constant AoE damage will hit Dark Willow even in Shadow Realm. Its automatic damage will hurt her if she tries to get close and use Bedlam.
Undying
* Decay can be good against Centaur Warrunner, as reducing the health of Centaur can make 
Double Edge risky.
* His zombies do not proc 
Retaliate, as it only procs for regular attacks.
Undying
* Undying saps strength from heroes with Decay, and Ogre Magi's high strength gain will allow Undying to steal more and more strength, becoming stronger with each use.
* Due to the Strength steal from Decay, Undying is normally very tanky, and has high health, making it harder for Ogre Magi to kill him.
Bristleback
* Viscous Nasal Goo slows down Dragon Knight and lowers armor, locking him down and making him more vulnerable.
Bristleback
* 
Spirit Breaker's 
Nether Strike with 
Aghanim's Shard disables Bristleback's passives.
Undying
* Due to Spirit Breaker's low attack speed, Tombstone is problematic for Spirit Breaker as the zombies summoned from Tombstone apply a stacking movement speed slow, which can significantly reduce Greater Bash's damage.
* Soul Rip and Decay allows Undying and his allies to survive and recover from any incoming ganks by Spirit Breaker.
Bristleback
* Heroes who can continue dealing damage even while being stunned: Luna, Razor, Axe, Bristleback, Leshrac, Death Prophet, 
Jakiro.
Undying
* Spectre must chase for kills and relies on movement speed for mobility in fights, and has no way to counter the Tombstone zombies.
* The potency of Soul Rip can be increased from nearby illusions from Haunt.
* Decay will shut down Spectre during the laning phase by effectively cutting down her initial health pool.
Additional:
* Spectre must chase for kills and relies on movement speed for mobility in fights, and has no way to counter the Tombstone zombies.
* The potency of Soul Rip can be increased from nearby illusions, so Undying can use 
Haunt against Spectre.
* Early game Decay will make Spectre easy to shut down in lane.
Bristleback
* Lycan's wolves deal little damage to Bristleback, and are easily killed by Quill Spray, even when they're invisible.
* Lycan's lack of burst damage makes it very hard for him to kill Bristleback, especially when his back is turned.
Additional:
* Quill Spray can be used to kill Lycan's summons.
* Bristleback allows him to stay alive against Lycan while dishing out counter attacks
* He can overpower Lycan with his Warpath instead.
Bristleback
* Bristleback's constant harass from Quill Spray will greatly hurt Enigma's laning and kill his Eidolons.
* However, Bristleback has no way of canceling 
Black Hole at all. And Bristleback is not a hero that goes for disabling items to counter that problem.
Bristleback
* Quill Spray destroys spiderlings, and hits Broodmother even when she's regenerating in her webs. This makes Bristleback one of her hardest counters in lane.
Additional:
* Bristleback reduces most of Broodmother's and her spiderlings' damage.
* Quill Spray will hit any spiders in its proximity, hindering Broodmother's fighting and farming capabilities.
Bristleback
* Lone Druid and The Spirit Bear cannot burst down Bristleback due to Bristleback
* Bristleback can easily run to Lone Druid without any hesitation, with Viscous Nasal Goo to reduce armor and slow the Spirit Bear or Lone Druid and Quill Spray can deal damage to both Lone Druid and the Spirit Bear at the same time
Bristleback
* Quill Spray is very effective against Io, as it has very low armor and has to stay close to the fight to not break its Tether.
Bristleback
* Fortune's End cannot dispel Warpath stacks on Bristleback or Quill Spray stacks on allies.
* Bristleback can heavily reduce Oracle's damage output. With it, Oracle may accidentally heal Bristleback with Purifying Flames, especially if Bristleback has bonus magic resistance.
Undying
* Winter Wyvern cannot handle the Zombies created by Undying's Tombstone very well. In most situations, Zombies will have more movement speed than her.
* Undying can gain one or two easy Decay stacks on an ally in Cold Embrace. The ally will still take the damage as well.
Additional:
* Winter Wyvern cannot handle the Zombies created by Tombstone very well. In most situations, Zombies will have more movement speed than her.
* Undying can gain one or two easy Decay stacks on an ally in Cold Embrace. The ally will still take the damage as well, since it is magical.
Bristleback
* Heroes with damage-over-time abilities easily allow Bristleback to turn his back in order to proc Bristleback continuously and to massively reduce to damage dealt to him: Arc Warden, Venomancer, Luna.
Undying
* Generally, any fragile heroes will have a hard time dealing with Undying's tankiness, and even more so if Decay is used on them. Some examples are Crystal Maiden and Witch Doctor.
Bristleback
* Axe, Bristleback, 
Centaur Warrunner, Spirit Breaker, Pudge, 
Huskar, Wraith King, Doom: These heroes are too tanky for Puck to burst down. Also, all of them have spells which can deal with and shut Puck down reliably.
Bristleback
* Bristleback's Viscous Nasal Goo can catch and slow Bounty Hunter. Warpath and Quill Spray can defeat him quickly due to his small HP pool when compared to Bristleback's.
Undying
* 
Chaos Knight's multiple illusions from 
Phantasm can destroy Undying, as Soul Rip can't offset the damage from the high amount of damage from his illusions.
Bristleback
* Quill Spray quickly destroys Chaos Knight's Phantasms.
Undying
* Huskar's huge damage output and attack speed can get rid of Undying and Tombstone quickly.
Bristleback
* The damage from 
Burning Spear can be reduced by turning away from Huskar.
* Bristleback can bait Huskar into using 
Life Break on him, then turn around and receive very little damage.
Additional:
* Bristleback's tankiness and Bristleback allow him to outlast Burning Spears' damage-over-time at almost any point in the game. In addition, if Huskar chooses to cast Life Break on Bristleback, Bristleback can simply turn around before it hits and receive little damage.
* Viscous Nasal Goo will reduce Huskar's low armor even further, and Quill Spray and Warpath will tear him down extremely quickly.
Undying
* Meepo can quickly destroy Tombstone thanks to 
Divided We Stand.
Bristleback
* Quill Spray usually hits Meepo's clones, although Bristleback cannot turn his back when rooted with 
Earthbind.
Undying
* Phantom Lancer's many illusions will easily destroy Tombstone, provided he has sufficient farm.
* He also has no ways of dealing with the illusions, since Decay doesn't steal strength from illusions.
Bristleback
* Bristleback's tankiness and damage reduction from the rear makes him very hard for Phantom Lancer to chase and finish off, due to his lack of burst damage.
* Quill Spray quickly destroys Phantom Lancer's illusions.
* Bristleback's passive costs no mana, meaning that it will continue to trigger even if Phantom Lancer drains Bristleback's mana with 
Diffusal Blade.
Additional:
* Bristleback's tankiness and damage reduction from the rear makes him very hard for Phantom Lancer to chase and finish off, due to his lack of burst damage.
* Quill Spray destroys Phantom Lancer's illusions.
* Bristleback's passive costs no mana, meaning that it will continue to trigger even if Phantom Lancer drains Bristleback's mana with Diffusal Blade.
Undying
* Tombstone can be stolen to counter-initiate the enemy team in skirmishes.
* Tombstone provides vision over the enemy around, use this to Rubick's advantage for more spells.
* Since Undying is melee and has low attack speed, the tombstone can be hard to taken down by Undying himself.
* Flesh Golem provides Rubick with increased Health pool and a powerful attack modifier.
* 
Rubick can apply the Flesh Golem debuff much more easily as a ranged hero.
* Decay is a decent damaging ability, making Rubick somewhat tankier in teamfights.
* Soul Rip can be used for extra heal or burst damage.
Additional:
* All abilities from Undying easy to steal to Rubick with 
Spell Steal.
Bristleback
* Bristleback's abilities are nearly useless for Rubick to Spell Steal, as he does not gain the bonuses from Warpath.
Additional:
* Rubick deals little damage on his own, and Bristleback can simply shrug off all his spells and chase Rubick down with his Quill Spray and the damage bonus from Warpath.
* Rubick does not tend to charge forward in teamfights, stay in the front lines under most circumstances, yet effective casts of Quill Spray and Viscous Nasal Goo requires the opposite as they require multiple casts and close range to add up stacks.
* Rubick does not benefit from Warpath through casting the stolen spell.
Bristleback
* While Jakiro's damage is going to be little more then average against him due to his Bristleback. His large quantity of stuns can prevent Bristleback from getting his much needed Warpath stacks, while also giving his allies a chance to counter his high defense.
* Dual Breath and Liquid Frost both reduce Movement Speed, removing one of Bristlebacks greatest strengths.
* Liquid Fire reduces Bristlebacks Attack Speed, making it harder for him to burst down a hero with Warpath.
* However Bristleback can generally catch and kill a lone Jakiro. And Jakiro is only effective in a group.
Bristleback
* 
Macropyre's frequent damage ticks causes Bristleback to activate repeatedly, resulting in free damage as long as Bristleback faces away from Jakiro.
Bristleback
* Axe forces Bristleback to turn around with 
Berserker's Call, allowing allies to attack him without fear of his passive.
Bristleback
* Heroes who can stop Axe from getting close will severely inhibit his presence in fights: Bristleback, Crystal Maiden, Batrider, Arc Warden, 
Winter Wyvern, 
Clockwerk
Undying
*
Arcane Curse can effectively discourage Undying from casting his spammable abilities in a team fight, as Undying will have to suffer more damage and the slow due to the penalty duration of Arcane Curse.
Last Word and 
Global Silence are able to silence Undying for up to 6 seconds, preventing Undying from gaining strength and healing his ally or himself.
*
Bristleback
*
Arcane Curse stacks every time Bristleback uses an ability, forcing him to stop spamming his abilities, or take heavy health degeneration.
Glaives of Wisdom steals intelligence both permanently and temporarily, causing mana issues for Bristleback.
Last Word and 
Global Silence stops Bristleback from using his abilities altogether.
Viscous Nasal Goo or 
Quill Spray while silenced, effectively blocking a major part of the hero's damage and preventing 
Warpath charges from stacking.
*
*
Additional:
* Bristleback will not be able to cast
* Arcane Curse slows Bristleback down and lasts longer the more abilities he uses. On the other hand, if he doesn't use any abilities, he will begin to lose Warpath charges.