An Algalon has the following abiltties:
Phase Punch: this ability has a 15 second cooldown, when it reaches 5 stacks, the tank is phased. The debuff has a 45 second duration, so 2 tanks need to rotate by taunting Algalon when it reaches 2-3 stacks.

Big Bang: it has an 8 second cast time, cannot be interrupted, everyone except the current tank must run into the Black Holes to survive. Algalon casts this roughly every 75 seconds. When the spell hits the "outside", players are phased out from the Black Holes automatically. The damage Big Bang deals is physical, the current tank has to use CD abilities to survive the mitigated damage and the time until the healers return.

Ascend to the Heavens: this ability is used to wipe the raid if noone is attackable by Algalon, if players ran into the Black Hole too early or if the tank dies while everyone is inside the Black Hole. Players inside the Black Hole are also affected (fragged) by it.

Cosmic Smash: it has a 25 second cooldown and a 4 second cast time, during which a red impact zone will appear on the platform somewhere (in 25man 3 impact zones will appear). Damage dealt by Cosmic Smash is proportional to the range the player has from its center, it can be as low as 3K. At very close, in addition to the high damage, it also has a deadly knockback effect that shoots you high into the... cosmos so that fall damage will surely kill you.

Enrage: Algalon's enrage timer is 6 minutes.

There are also four adds, which include:
Collapsing Star - These adds spawn in packs of 4 when Algalon yells "The stars come to my aid". They have no threat list, their HP decrease on their own as well as from player damage. When a Collapsing Star dies, a Black Hole Explosion hits the entire raid, so their deaths (and the Cosmic Smashes) must be timed to avoid wiping the raid. When it dies a void zone looking area spawns around the star and inside a portal appears that leads to the Black Hole. The void zone doesn't deal damage, and you don't have to click on the portal to active it, just stand on it.

Living Constellation - These adds have 261K HP on normal mode, they use Arcane Barrage to deal 4.5K damage on average. If they are pulled into Black Holes, they close them. Unlike the Collapsing Stars, they do have threat lists, which must be managed by tanks to protect the healers.

Dark Matter - They look like Wraiths (just like the ones in Stratholme), they can be found inside the Black Hole and players must evade them while waiting for the Big Bang's cast to finish. All Black Holes lead to the same place so the 9 or 24 players share the same phase.

Unleashed Dark Matter - at 20% Algalon will yell "Behold the tools of creation" and summon 4 adds. It is recommended to just tank them and not kill them.