eq mob:Laskuth the Colossus (Regular Raid)  

Can hit for ~2200; banishes its target to an area further inside the room (a short distance).

Upon death:

Laskuth the Colossus's corpse crashes down onto the frozen waterfall, shaking the menagerie and spraying shards of ice in all directions.

Your victory has shattered the shroud of magic surrounding the dungeon's treasure.