The crotch catapult is a button-activated, spring-loaded machine that was designed by Jake for Giant Foot Finn to hit evil monsters in the crotch. It is seen in "Freak City." Jake creates the crotch catapult in order to show Finn the advantages of being a giant foot. Finn originally hates the idea, saying "This sucks dude." Not long after Finn is prepared on the catapult, Two Headed Monster comes running and steps on the button. The catapult works flawlessly and Finn subsequently hits him in the crotch. As Two Headed Monster is yelling out in pain, Jake grabs Finn and runs away. Jake encourages Finn by telling him that even as a foot he is still a great hero, but Finn does not seem convinced whatsoever by the ordeal.
The crotch catapult consists of a large button with a red "X" on it. There is a long wire running from the button to a spring. As a foot, Finn rests upside-down on the spring. When a monster steps on the button the spring is activated and Finn flies, hitting the monster in the crotch.