Super Mario World 2: Yoshi's Island/Bosses/Hookbill the Koopa

Hookbill the Koopa is a magically empowered Koopa Troopa, and the final boss of World 4 in Super Mario World 2: Yoshi's Island. His name stems from his large hookbill jaw, hence the name.

Strategy
To defeat Hookbill, one must pelt him with eggs until he falls over, and then pound under his belly.

This must be done three times to win the battle. Hookbill has several different attacks. First, he will crawl to you on all fours, causing you to drop Baby Mario if he touches you. When you pound his stomach, he withdraws into his shell and start bouncing around before proceeding to his next attack. After being wounded once, he gets up on two legs and starts running, again causing you to lose control of Baby Mario if he comes in contact with you. For his final attack, he will jump and attempt to body slam you. Once Hookbill is defeated, he falls off of the edge.