S1E12: Gorilla

Beast Boy turns into a loud, obnoxious gorilla and refuses to change back driving Robin crazy. Gorilla Beast Boy takes over the leadership of the Titans leading to chaos ranging from not letting a girl get onto Beast Boy's monkey bars, fighting crocodiles, and freeing captive gorillas from the zoo. Cyborg teaches Robin how to be an alpha male so he can take back his role as leader of the Teen Titans.