Make it shoot its explosive, firey wither skulls
Naturally pulling objects into itself
Make tractor beams have a chance to unfreeze props and destroy welds
Add a option that makes NPCs get killed like players instead of just disappearing
More sound effects and ambiances (such as it roaring on occasion)
Music dynamically change when it changes phases (when phases are added)
Tentacle attacks
And if possible make the tractor beams pull in nextbots.