There was a hidden passage on the side of the solo dungeon I was in and it had two copies of this boss glitched inside each other. I killed the solo version but the other one is a group version and has group HP scaling. This is a low level dungeon.
Hi @KingCurrency thanks for the report!
Best way to report such bugs is to use #bug command in game:
Example: #bug there's a hole in the ground here.
This method is the best way to report any environmental bugs (misplaced objects, resources stuck in other objects, invisible walls, holes, missing textures etc) because coordinates of your character are sent along with the report so you don't have to post a screenshot or explain where exactly the problem is.