El Chupanibre

El Chupanibre is a sewer monster that once terrorized the mutants below New New York. He is a giant green humanoid lizard with massive yellow teeth and claws. He was flushed down the colossal toilet to the sub-sewer by Bender in the course of saving Nibbler. But in later episodes, he is seen back in the regular sewers.

It is possible that El Chupanibre was once a mundane animal or even human that was transformed into its current shape via the mutagenic properties of the waters in the sewers.

Trivia

 * The name "El Chupanibre" is based on the Puerto Rican and Mexican myth of El Chupacabra, which means "the goat-sucker". The monster supposedly sucks the blood of goats and other livestock. However, the suffix "nibre" is gibberish, so the name "Chupanibre" has no direct translation.