I had this idea for a Raid battle.

It's called Demon Diamante of Sardonicus (DDoS)

It's a giant diamond with a twisted grin on its face that banishes players to a room above the battlefield that looks like the character select screen, with music. After several seconds, the floor vanishes momentarily, dropping the players back into the battle.

Other attacks could include being teleported to a room above the banishment room and the player is dropped into the other banishment room momentarily.

It can also hit people with an affliction to scramble movement controls as well as bind them in place.

The usual aoe attacks still apply.