The fly turns into the fighter, the mouse turns into the super mouse, the cat turns into the ferocious feline, Pluto turns into the attack dog and finally, the fire hydrant turns into the living hydrant.
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.—Jon Reeves <jreeves@imdb.com>
