Paying the Piper (1949)

Pied Piper Porky Pig vows to rid the town of Hamelin of all its rats, and the cats of Hamelin are furious at Porky for usurping their rat-catching job. Disguising himself as a giant rat, the "grand poobah" of the cats intends to discredit Porky in the eyes of the town's mayor, by making it seem that Porky hasn't entirely fulfilled his promise to remove every last rat.