Instructions
Stomp on three of the purple tiles on the roulette wheel to initiate the battle.
Spray water from your F.L.U.D.D. device onto King Boo's large tongue. Eventually he will grab a nearby slot-machine. If you run out of water, pop the bubbles King Boo spits out to refill your tank.
Spray the slot machine to make the reels spin. If three question marks line up, prepare to fight a small group of enemies. If three coins line up, your coin bar will fill by three slots. If three fruits line up, fruit will pour out of the machine.
Grab one of the red peppers that came out of the slot machine and throw it at King Boo's tongue. This will cause him to panic and try to relieve the burning sensation. Do not spray his tongue with water, as this will cool the heat and cancel the distracting effect of the pepper.
Grab another piece of fruit while King Boo is distracted and throw it at his head. This will cause the King to stagger, but his disorientation will be short-lived.
Repeat steps two to five, two more times. After being hit on the head with three pieces of fruit, King Boo will be defeated.