XT - 002 Deconstructor XT - 002 Deconstructor is the fourth raid boss in Ulduar raid . He directly blocks the entrance into the lower level of Ulduar in the Scrapyard . The fight is a rather straightforward gear check . A companion version of this boss , Lil ' XT , is available from the Blizzard Pet Store . Background . Engineered by Mimiron , he dominates the Scrapyard area of Ulduar and considers himself his inventor ' s son . This causes the machine to behave like a young boy . Strategy . Preparation . As with all Wrath of the Lich King raids , a standard raid composition is OK . No special resistances or equipment are needed . In Normal 10 - man mode , damage dealers should average about 3 , 000 DPS ( 3 , 500 DPS if using only 5 damage dealers ) . Normal 25 - man requires the entire raid to output approximately 60 , 000 DPS . Heroic 25 - man mode requires damage dealers to provide 5 , 000 DPS each . Phase 1 consists of a fairly standard tank - and - spank . The fight enters phase 2 when the boss is at 75 % , when it takes a 20 - second " nap , " during which it exposes its heart and summons adds . After that , Phase 1 continues until at 50 % ( and 25 % again ) a Phase 2 takes place . Gravity Bomb and Light Bomb . Each raid member must learn to deal with these two debuffs . Since they both are a threat to other raid members , debuffed players must separate from the raid as fast as possible . Melee can set up in a circle around the Deconstructor , since it has no cleave or short - range AoE . Healers and ranged DPS should stay 10 yards away from tanks and melee , and then agree on one of the following set - up possibilities : It ' s also possible to set up in a wide circle around the tank spot , with as much space between players as possible ( preferably around 10 yards ) . The Deconstructor keeps the two Bomb debuffs up at all times ( that is as soon as one of them expires on a player , another player gets it ) , except during Tantrum , when the Bomb debuffs are not refreshed . The two players with Bomb debuffs must run away from all other players , either to explode in safety ( Gravity Bomb ) , or in order not to damge others ( Light Bomb ) . Gravity Bomb does not kill , so if that player starts at full health , no healing is required . Light Bomb can kill , for that reason one healer should be assigned to put a HoT or two on the current Light Bomb victim . Even with fast player reaction , Light Bomb inevitably deals some AoE damage to the raid . The raid healer ( s ) need to be quick to AoE heal this . Tympanic Tantrum . Once per minute , the boss casts Tympanic Tantrum . The one - minute cooldown is reset by exposing the heart ( getting below 75 % , 50 % or 25 % respectively ) , so high - DPS groups can completely avoid Tantrum . If the boss casts Tantrum , every raid member takes 80 % damage within 8 seconds , and is slowed by about 40 % . This means that AoE healing must be well organized so that nobody dies from this damage , and that the raid should be on top health prior to Tantrum . The standard avoidance methods do work , but reduce DPS ( which may prove fatal ) . Hunter Deterrence is ineffective but Rogue Feint does reduce Tantrum damage . The damage can also be mitigated by a paladin ' s Divine Sacrifice coupled with Hand of Protection or Divine Shield , as well as a Discipline - specced priest ' s ( with a shorter cooldown from Soul Warding , and 3 % raid - wide damage mitigation from Renewed Hope ) . Phase 2 : Exposed Heart and Adds . Whenever the boss gets below a 25 % threshold ( at 75 % , 50 % and 25 % ) , it switches for 30 seconds to Phase 2 . During this time , the boss itself cannot be targeted , but it exposes its heart and takes double damage , and adds are summoned . Three types of adds spawn from the scrap heaps in the four corners of the room : The Scrapbots need to be AoE ' d down and must not reach the boss . They are susceptible to most snares ( stun , frost nova , knockback , etc . ) . The Boombots should be single targeted and nuked by ranged . It is best if they explode when surrounded by scrapbots or near the Heart . The Pummelers should simply be off - tanked and kited during the whole fight around the room . No damage dealer should ever target a Pummeler . Scrapbots spawn in ~ 7 - 10 groups of 5 . The groups can appear simultaneously and at varying times . Have people keep an eye out and call out where and when they are coming . When scrapbots get closer to the raid group , they need to be AOE ' d down immediately ( a Priest using Mind Sear can help reduce the number of DPS wasted on scrapbots ) . Boombots need to be DPS ' ed when they are near the Heart or scrapbots ( or when not close to players ) . from Engineers can be extremely helpful to stop the closest Scrapbots , stunning all mechanicals within roughly 20 yards for 3 seconds . When the heart goes back up into the boss and XT becomes targettable again , the remaining active adds stay alive . The Heart has 7M hitpoints in Heroic mode ( 1 . 5 M in normal mode ) . Since the heart takes double damage , and all damage it takes is passed through to the boss , every damage dealer should try to concentrate on the Heart as much as possible . Melee should stay on the heart exclusively during the whole phase . Even healers can deal some damage in this phase , Mana permitting ( else healers can use this phase to regenerate a little ) . While it ' s desirable to deal as much damage to the heart as possible , destroying it invokes hard mode , pay attention that this doesn ' t happen by accident . Bloodlust should be used during a heart phase and extra attention should be paid not to trigger the hard mode if this is undesirable . Dealing with a low DPS raid . If the raid ' s damage output is on the low side , the key is to maximize the damage done to the heart in phase 2 . The idea is to divert two players to slow the adds down , while all other damage dealers concentrate on the heart . Position the boss close to two scrap heaps ( and far away from the two others ) . The adds from the two far away heaps cannot reach the boss before the heart is retracted , thus two players ( e . g . mages ) are sufficient to slow down the adds from the two close heaps . As soon as the heart retracts , all ranged DPS nuke the adds . The luck aspect of this fight is having XT - 002 cast Tympanic Tantrum just before going into Enrage . This yields an extra 5 – 10 seconds DPS time , before he obliterates the raid . At this point , all healers ( besides the one healing the Pummeler Tank ) should give as much DPS as possible . Quotes . Sound Files . See " Sound Files of Ulduar : XT - 002 Deconstructor " Related achievements . The following achievements are for the encounter ' s hard mode .