Hippety Hopper

A mouse is about to commit suicide by jumping off a pier when he is saved by baby kangaroo Hippety Hopper. In exchange for the mouse releasing him from his shipping crate, Hippety agrees to help the mouse humble his tormentor, Sylvester Cat, by making Sylvester think that vitamins have enlarged the mouse to Hippety's size, and when Sylvester fights the "giant mouse", he loses in the usual embarrassing way- this time, in front of a chiding bulldog.