Mad scientist Mickey has just brewed up a potion; to test it out, he squirts it on a fly that's been trapped by a spider, a (regular) mouse being harassed by a cat, then the cat when Pluto goes after it, and Pluto when dogcatcher Pegleg Pete goes after him. Each of the underdogs turns against his tormentor.

Credits

Ben SharpsteenDirector

Walt DisneyMickey Mouse (voice) (uncredited)

Pinto ColvigPluto (voice) (uncredited)

Billy BletcherPete - Dog Catcher (voice) (uncredited)

Clarence NashSpider / Cat (voice) (uncredited)