Having lain near-dormant since WoW's two expansions made it a cakewalk, Onyxia's dungeon will be permanently converted to a 10-player normal raid and 25-player Heroic, scaled up and revamped to present a challenge to today's tricked-out level 80 heroes.

"We will also be updating the encounter mechanics to be more fitting for modern raiding," says Blizzard, "but we can guarantee players will get to experience the frightening horror of deep breaths once again."

New items will be added using the same models as vintage Onyxia loot for that classic 2005 look, as well as a 310% speed Onyxia Broodling flying mount.

As a bonus, all players who login during "a limited time" after the anniversary event begins in November will receive a special Onyxia Brood Whelping pet.