The Impossible King Slime is a pre-impossible boss.
He is a MASSIVE slime, roughly 25x bigger than the Rainbow Slime
Impossible King Slime can spawn under one of the following conditions:
- A player uses an Impossible Slime Crown
- 22,500 Slimes are defeated in the slime rain/5,625 if he has been already defeated.
- Rarely in the outer thirty sixths of the map, during daytime and only on grass.