First off, I've not tackled with most of the raid bosses in WoW (although I started with Vanilla, I quit halfway through BWL and started again with WotLK as a super-casual, meaning I missed out a lot of content!) so if this idea is similar to any other raid encounter my apologies! Probably not the most original idea, but hopefully you guys like the idea of it and would want to tackle it.
The Boss
Basically looks and who the boss actually is, is completely undecided at the moment. The only thing concrete is what it does and how to tackle it. The boss in question won't be too difficult, at first. When the raid first encounter it, they'll notice that it isn't too powerful in regards to its melee/magical strength.
HP: 6,000,000
The Twist: Every 30 seconds the boss creates a duplicate of itself. The duplicate's HP is the sum of the original's HP (at the time of the split) + 30% (i.e. If you take the boss down to 3,500,000 health in 30 seconds, the duplicate will have 3,500,000 + 1,050,000 = 4,550,000HP). After the next 30 seconds, the duplicate then duplicates itself and the cycle continues (after 60 seconds, there would be 3 versions of the boss etc.). It's always the newest version of the boss that duplicates, so it's their HP that gets taken into consideration.
Each version of the boss (including the original) has an aura. This stackable aura raises all forms of damage by 30% to all duplicates/original in a 30 yard radius. All versions need to be killed in order for the boss to be truly defeated. Killing the original will only make the oldest duplicate the new original, and therefore all versions must be killed.
Abilities
Aside from normal melee/magic abilities, each version has the ability to use:
- Immolation. Basically this will do a ton of damage to melee damage dealers per second for 10 seconds. This ability is used frequently but not simultaneously amongst the duplicates. This forces the melee DPSers to either switch between duplicates or simply hang back.
- Teleport Switch. This allows the boss to switch places with any random raid member.
- Ice Block. Surrounds the boss with ice making it immobile but immune to all kinds of attacks/spells and also inflicts a lot of damage per second to anyone in an 8 yard radius. Lasts 10 seconds and only occurs right after Teleport Switch.
EDIT: Both Ice Block and Teleport switch will not be used by the newest copy (inc. the original when it hasn't duplicated).
Strategy
Obviously DPS will have to be on top form to get the boss' health down as quickly as possible, as it will inevitably create a duplicate of itself after 30 seconds. The new version will have more HP than the original and must be tanked/spanked on its own and 30 yards away from the original (to avoid them from benefiting the Aura). Damage Dealers and Healers will have to organise their positions so that they're 30 yards away from the version of the boss they're not fighting. This is to avoid the negative effects of Teleport Switch. The boss may switch with a raid member and cast Ice Block on itself, and if another version is nearby they will receive the benefit of the aura. If this occurs, the tank must move the other version 30 yards away. This proves more difficult the more versions there are at one time.
Although the version with the lowest health (the original's) being taken down first seems obvious, some DPS must be applied to the newest version to get its health down swiftly, so that when they duplicate, said duplicate will spawn with as little health as possible. It will also be better to switch DPS onto the newest version, so that their duplicate will receive very little health. This tactic, however, would likely mean that the raid will have to manage multiple versions at once.
Hard Mode Achievement
You must let the boss duplicate itself at least 9 times without killing a single version before you truly defeat it.
The only way this can be feasible is if DPS whittle down the original's health as fast as possible and then switching to the newest duplicate when it spawns (but leaving 2 members behind to deal with the previous version) and finally going all out when there's a total of 10 versions. Every raid member will have to be on top form to manage 10 versions of that boss at once, making sure those aura's don't stack and quickly moving in the right place when it inevitably does (due to Teleport Switch and Ice Block).