Captain Skull, the Sparkle Land boss, is an undead pirate that appears in Wario World. Being the last of the game's four major bosses, he holds the last Giant Treasure Chest Key and is the last boss before the final boss. He has a hand cannon for one arm and a grappling hook for the other arm. He makes use of the cannon by blasting energy projectiles and flaming cannonballs at Wario from a long range. The hook can be used to get Captain Skull to another part of the arena.
Wario battles him on a wrecked pirate ship with a gaping hole in the middle. Each half has a main deck and a crow's nest. On both halves, a spring is there to catapult Wario high up to the crow's nest (Wario can also manually climb there via a ladder). The two halves of the ship are separated by water, but fortunately, a stone slab at the base of the arena can be used to cross.
Being the second-to-last boss, he has a variety of different attacks. Captain Skull may fire multiple flaming cannonballs at Wario from the cannon on his arm. The cannonballs pose a danger even after they've cooled, as they can still explode a few seconds later. Captain Skull can also shoot large blue beams at Wario, as well as his pink energy balls that home in on the Wario. If he charges energy into his cannon, Captain Skull will launch a gigantic cannonball that makes a huge explosion on impact. Wario should be on the crow's nest if Captain Skull aims for the main deck and vice versa. After losing a few skulls of health, Captain Skull blocks every punch thrown at him by Wario with by using his cannon arm as a shield. If Wario continues to punch him whilst he does this, he becomes enraged and flashes. He then executes a spinning attack, which is his one and only close-range attack.
To defeat the boss, Wario starts off having to get close to him and punch away at him until he is stunned. He then needs to pick him up and execute a Piledriver to knock out one of his five health skulls. After losing three health skulls, Captain Skull becomes nearly impossible to stun due to him blocking Wario's punches. Wario needs to throw projectiles at him to continue damaging him. The player must use the glowing energy rings to bounce up to a lookout tower when Captain Skull is atop the opposite one. Eventually, Captain Skull fires volleys of flaming cannonballs at Wario's lookout tower. Wario must pick one up after it cools off and face Captain Skull in the opposite tower. The player must charge up a Power Throw, aim at the boss, and fire at him. Wario then must move quickly to reach him. Wario must jump down off his tower and land on the glowing energy rings, which propel him high into the air. After landing on the opposite energy ring to bounce up to the Captain's lookout tower, the player then must pick up the stunned Captain and execute a Piledriver. Wario must repeat this process until he has knocked out all of his health skulls, defeating him. Wario then receives the fourth and final Giant Treasure Chest Key.
Another way to knock out Captain Skull is to simply pick up a barrel (before Captain Skull blows them up with his explosion attack) and smack him with it.