Chimaeron Chimaeron is an altered hydra boss of the Blackwing Descent raid instance . Abilities . Be sure to talk to Finkle before aggro - ing Chimaeron in order to gain the buff : Strategy . Phase 1 . There are three basic phases to the fight . When the Bile - o - Tron is online the raid will spread out , the buff will protect them from being one shot by Caustic Slime and Massacre . Healers need only heal people to above 10 , 000 HP . It is very important for healers to control their ingrained " panic " reaction when people are low on health - if they try to keep everyone topped off they will quickly run out of mana . When the Bile - o - Tron is knocked offline by Massacre Chimaeron ' s heads will begin fighting each other but will still cast Caustic Slime . Thus the raid will stack up on top of each other and will need to be healed as much as possible . You should assign 1 - 2 large AE cooldowns to be cast per each Feud phase , such as Divine Hymn , Divine Guardian , Tranquility , etc . Any nature resist buff ( aspect , totems , etc ) you can cast is also EXTREMELY helpful for this phase . Damage is split between all targets hit , however pets ( temporary or otherwise ) are never hit and thus do not help soak damage . When the Bile - o - Tron comes back online the raid should spread out again . Phase 2 . Shortly before 20 % , you should aim to heal everyone above 10k health . At 20 % HP Chimaeron will become untauntable , take extra damage , and apply a debuff to the raid reducing healing done by 99 % . You will still have the Bile - O - Tron , which means that any players above 10k health can survive 2 attacks from Chimaeron . At this point it ' s a simple burn . Because of the lack of healing , healers should help DPS . All DPS should use survival abilities : Rogues evasion , Priests fade , Mages mirror image , Hunters Deterrence , etc . In the 10man version , the " burn phase " can be somewhat challenging due to " running out of bodies . " In the 25man version , the " burn phase " is generally viewed as a free kill assuming that you have 20 + people alive . Strategy 1 . Simple in concept but more difficult in execution , Chimaeron is a gear check boss . This fight requires 2 tanks ; one will take all regular melee attacks , and the other will taunt off and take only the double strike attacks . The boss attacks extremely slowly ( around 5 seconds inbetween each attack ) so the regular melee tank will only need 10k hp for each hit . The offtank however needs to be topped off due to the double strike mechanic . Double Strike causes the boss to gain a buff which will make his next attack hit twice at once . You want to have the first attack leave you with more than 10k hp , so that the next attack will not kill you . Each attack is about 100 - 150k damage unmitigated , thus the need for full health on each double strike ( barring a lucky dodge / parry / miss ) . Due to the " Break " debuff , you can not have just one person tank it all due to the fact that the increased damage taken debuff from break will cause the first double strike attack to do enough damage to leave less than 10k hp remaining , which makes the second attack kill you . Thus the overall objective is to have all break debuffs stacked on the normal melee tank , while the offtank gets no break stacks and takes only double strikes . Strategy 2 . Once your tanks have some epic gear , you should use 2 tanks that swap at 2 - 3 stacks of break and simply soak the double attacks . This means that the current tank must be topped off at all times . Heroic Changes . In the heroic version of this encounter , there are two major differences : Bile - o - Tron offline .