Teenage Mutant Ninja Turtles (2003) - Season 1 Episode 13 -

When Don's examination of some mysterious crystals attracts the attention of a subterranean monster, the Turtles underground exploration unearths a Foot Genetics Lab! A video record of strange experiments reveals more of Shredder's mysterious agenda, but when the mutants attack, the boys better watch out, or it's everybody out of the gene pool!