Containment System Abuse
The final boss of the Mermalair is Prawn. After SpongeBob shuts down the security system, Prawn is released from the Villain Containment System. Prawn is surrounded by disco tiles that flash rapidly. The fight consists of dodging his sonic waves and Ham-Mer robots. After Prawn's attacks finish, the disco floor reveals a lane to shoot a bubble bowl. Prawn takes 3 hits to defeat.
At the inner rim of the disco tiles, a small spot exists that SpongeBob can stand without getting damaged. Standing in this spot while holding forward allows the player to avoid risking damage. From here, Prawn can be bowled 3 times and defeated.