Fry: So, is it true that alligators flushed down the toilet survive down here? Green Mutant: No, that's just an urban legend. Bender: Then what are those? Green Mutant: Crocodiles. Three-armed Mutant: We keep them as pets. Then, when they grow too large, we flush them down into the subsewer.

(Thanks to Sewerfriend Heather Gilmer for this item.)