I was thinking, what about a super/elite boss that spawns from side room treasure chest with a low spawn rate and can only be done in synced requirement, they seal off the room they spawn in and must be killed to advance or if the party dies. If whole party dies the boss will disappear (Sorta similar to critical engagement, but for dungeons). They drop good rewards if beat but if not when they vanish due to a wipe, the party will get a permanent weaken state de-buff until the end of the dungeon. Thought about this while I was looking at my Shinryu minion lol. But it is an idea progress.