Algalon the Observer Algalon the Observer is a hard mode - only encounter in Ulduar , released in patch 3 . 1 . Background . Algalon is a constellar sent by the titans after Watcher Loken ' s death activated a planetary fail - safe protection , indicating possible distress on Azeroth . Algalon ' s task is to analyze any systemic corruption on the planet . If it ' s deemed beyond saving , the Titans will " re - originate " the planet to cleanse it of corruption , killing all currently living organisms in the process . After his defeat in Ulduar , he chose to monitor the activities of the mortal races of Azeroth . His outlook on life and the Titans ' plans has been called into question , so he seeks to understand what makes Azeroth so different from the countless worlds he has observed before . Gaining entry to the Celestial Planetarium . Algalon can only be accessed if at least one member of a raid has obtained the or . Players used to have a one - hour window to defeat him per lockout period , starting upon first initiation of the encounter . However , since patch 4 . 0 . 3 , this timer has been removed allowing a raid to have unlimited attempts at the encounter . Blizzard has sardonically referred to him as " Algalon the Raid Destroyer " . Abilities . 25 - man . Algalon dual wields and his swing speed is extremely fast , with ~ 27 , 000 main hand and ~ 15 , 000 offhand swings coming every second or less . The Collapsing Stars have 1 , 764 , 000 life in 25 - man . 10 - man . Algalon dual wields and his swing speed is extremely fast , with ~ 18 , 000 main hand and ~ 10 , 000 offhand swings coming every second or less . Strategy . Phase 1 . Algalon transforms the arena into space and immediately begins attacking the player with the highest threat . Algalon hits very hard and fast ; he casts Quantum Strike on the tank with high frequency , so healers must ensure that the tank remains at full health at all times . All DPS merely attack the boss the best they can . Algalon can be positioned anywhere , as he has no frontal cleave or cone attacks . After 15 seconds , Algalon begins casting Phase Punch on the current tank every 15 seconds and also summons four Collapsing Stars . Once the tank gets 5 stacks of the Phase Punch debuff , that tank is ported out for 10 seconds as if he stepped into a Black Hole , whereupon the debuff is completely removed . Algalon then switches to the second highest on his threat table . Your off - tank should be ready to taunt , with healers ready to change targets , as the off - tank begins taking substantial damage very quickly . Algalon will be Phase Punching the tanks throughout the fight ; tanks must keep switching after . Assign one or two ranged DPS to kill the Collapsing Stars one at a time . Since they slowly lose health on their own ( 1 % health per second ) , if left alone , they will all explode at the same time and wipe the raid . Alert the healers so they are ready before a Collapsing Star is killed , as the entire raid takes roughly 16 , 000 shadow damage regardless of positioning ( a tank who is too low on health when a star explodes can die and likely cause a wipe ) . When a star dies , it leaves behind a Black Hole , which is both a void zone and a portal to another realm . Collapsing Stars keep spawning throughout the fight until Phase 2 and should always be killed . Every 25 seconds , Algalon casts Cosmic Smash on a random player , including a tank . This appears as a red fissure , which explodes after a few seconds . Everyone — not just the targeted player — should move away from the red fissure , as it causes splash Fire damage , based on player distance with the impact point . Note : On 25 - man , Algalon casts three separate Cosmic Smashes on three random players . Fifty seconds after the initial pull , Algalon summons three Living Constellations that cast Arcane Barrage on random players and have normal threat tables . It is unnecessary to DPS a Living Constellation . Instead , a single player can aggro these and run behind any available Black Hole , as any Living Constellation that passes through a Black Hole dies instantly , causing that Black Hole to disappear . The player assigned to do this should be careful to run " around " a Black Hole instead of through it to avoid being portaled . Death Knights are an ideal choice for this , as they can stand behind Black Holes and use Death Grip to pull the Constellations into the hole . Every 90 seconds from the initial pull , Algalon begins casting an 8 - second lethal spell called Big Bang . To avoid getting hit by Big Bang , everyone must enter a Black Hole created by a killed Collapsing Star " except for one person " . For this reason , all players should be aware of the location of remaining Black Holes after Living Constellations are killed . Players need not enter the same Black Hole as everyone else ; all Black Holes lead to the same dark realm . Once inside the Black Hole , players take roughly 1 , 500 Shadow damage per second and must avoid elite adds called Dark Matter scattered throughout the realm until Algalon finishes casting Big Bang , and automatically portals everyone back to the normal realm . If " everyone " enters the Black Holes and Algalon has no player in the normal realm to target , he kills the raid with Ascend to the Heavens , then disappears . For this reason , one player must remain in the normal realm to eat the Big Bang . A player protected with a Holy Priest ' s Guardian Spirit , a Shadow Priest casting Dispersion , a Fire Mage with 2 ranks in Cauterize , or a tank blowing " all " cooldowns are all capable of eating the Big Bang . Note : Big Bang ignores immunity effects such as Hand of Protection , Ice Block , and Divine Shield . Entering a Black Hole also resets all threat of the player . If the currently Phase Punched tank stays outside to eat the Big Bang , the off - tank can taunt to gain all the threat he had upon return to the normal realm , ensuring that the rest of the raid doesn ' t pull aggro . This phase continues until Algalon reaches 20 % . Phase 2 . When Algalon reaches 20 % , Collapsing Stars and Living Constellations despawn and stop respawning , and all open Black Holes disappear . Algalon continues to cast Quantum Strike , Phase Punch , Cosmic Smash , and Big Bang . Algalon then summons four new Black Holes in a square pattern . Every 30 seconds , four Unleashed Dark Matters will spawn , one from each Black Hole . The off - tank needs to pick these up and tank them to the side for the rest of the fight , and DPS must burn down Algalon before these adds pile up and become too much to handle . When this phase begins , consider swapping tanks , as the current tank will very likely have the Phase Punch debuff and the off - tank will have a hard time surviving if he has to tank the adds and Algalon together . If you swap once the Black Holes spawn , you ' ll be given about 45 seconds to defeat Algalon before a forced tank - swap which should be long enough . Players also need to keep alert about Cosmic Smashes as Algalon will still be using this . Once Algalon reaches 1 - 2 % , he is defeated , all adds and Black Holes despawn . Quotes . Sound Files . See " Sound Files of Ulduar : Algalon the Observer " Related achievements . The following achievement is given to the first raid group on a realm to defeat Algalon in a 25 - man raid : Notes . Trivia . Collapsing Stars and Black Hole adds . All stars at the end of their main - sequence life cycles undergo , where the core is compressed and heats up . If the density of the core exceeds a critical point , the star will eventually collapse to an almost infinitely dense " black hole " and release vast quantities of electromagnetic radiation in the most well known type of . A star with a core that contains more than 3 solar masses may collapse into a black hole . Normally , passing a black hole ' s event horizon makes it impossible to escape the black hole ' s gravitational pull , however players may freely pass between a black hole ' s event horizon due to gameplay purposes .