Gulp

Gulp is a starter move mastered by Mini-Yoshi during the events of Paper Mario: The Thousand-Year Door. It uses up 4 FP. The player must press and hold down the Button as Yoshi walks up to the selected enemy. When the gauge is full, the player should let go, and Yoshi will stop walking, hold the enemy in his mouth, and spit it into the ground-based foe that was closest to it, knocking one against another and dealing Defense Power-piercing damage to both. If there are no grounded enemies accompanying the target, Yoshi will only damage the selected enemy. Yoshi can hold spiked enemies in his mouth without hurting himself, but not fiery ones.

The move is the only known way to defeat the Iron Clefts, which are invincible to any other attacks. Also, defeating the Iron Clefts is Mario's first task requiring Yoshi.

Hacking the game has revealed that Gulp was intended to have a number of different special outcomes, such as Yoshi eating the enemy outright (with a special animation for eating exploding enemies) instead of swallowing it, or spitting out a giant fireball that damages all enemies (presumably for use after eating a fire-type enemy). The effect where Yoshi swallows the enemy whole was not completely removed from the game, and can sometimes be seen when Yoshi uses Gulp on a Pokey or Poison Pokey that has already had all its segments removed. Under this circumstance, there is a 50% chance that Yoshi will spit the Pokey out as usual, and a 50% chance that he will swallow it whole as in the (usually) unused behavior.