Archie's Weird Mysteries (1999)

S01E22 It Lives in the Sewers

Jughead has been heartbroken since Veronica accidentally sent his pet baby alligator, Peanuts, down the toilet and into the sewers. As he grieves, strange reports emerge about a monstrous creature lurking in the sewers, having grown to an enormous size due to a toxic waste leak. Could there be a connection between his loss and this bizarre situation?