Hookbill the Koopa

"It's m-m-my job to b-beat Yoshi, and I'm a g-gonna m-m-make m-mince meat out of that c-cocky little wimp!"

- Hookbill the Koopa

Hookbill the Koopa is a demented Koopa Troopa in the game Super Mario World 2: Yoshi's Island. He is the boss of World 4 and he resides atop the final castle in that world. When Blue Yoshi and Baby Mario reach the top of the castle where Hookbill lurks, a fog envelops the area as the Yoshi crosses the bridge. After the fog fades, Hookbill and Kamek appear before the dinosaur. Kamek threatens Blue Yoshi by saying "Little Koopa come through for me now! Go forth and rock Yoshi's world!" and then casts a magical spell on Hookbill. Hookbill pops into his shell, which proceeds to grow to an enormous size.

After the transformation is complete, Hookbill shows himself, having become a gigantic Koopa Troopa. Walking on all fours, he creeps towards Blue Yoshi to attack him and Baby Mario. After walking on all fours for some time, he stands up and runs in Blue Yoshi's direction and lunges at the dinosaur. Blue Yoshi then must dodge the attack in order to avoid getting hurt. To defeat Hookbill, Blue Yoshi must first throw Yoshi Eggs at the giant Koopa. If Blue Yoshi jumps on Hookbill's shell or head, Hookbill will cough out Yoshi Eggs for the Yoshi to use against him. Yoshi can then take aim at Hookbill's head and arms and fire eggs at the Koopa. After shooting him four times if he is walking on all fours, or three times if he is standing up on two legs, Hookbill will then fall on his back and begin struggling to get up. After jumping onto the oversized Koopa's belly, Blue Yoshi must then ground pound the shell, delivering damage to Hookbill. If Blue Yoshi fails to do so, Hookbill will eventually recover, and then hide in his shell and begin pounding the ground. Additionally, Hookbill will perform the same recovering counter attack right after Blue Yoshi ground pounds his belly. Blue Yoshi must complete this process a total of three times in order to defeat Hookbill. When Blue Yoshi lays the final attack on Hookbill, his shell will explode. The normal-sized Hookbill (in his boxers) will then pop out of the shell and fall off the top of the castle.

Hookbill the Koopa re-appeared in Tetris Attack as one of Bowser's allies in the game. Here, Hookbill the Koopa takes Phoenix's place of the original Panel de Pon at Stage 9. Additionally, Hookbill had no personal ally of his own, unlike many other characters. The game also implies that he speaks in a hasty and stressed way.