Andy Goldman

Andy Goldman is one of the oldest living mutants. He lives in the sewers of Old New York rather than those of New New York, this could be the sub-sewers. In the 20th century, Andy was Fry's Neighbour and presumably a normal human, although he was a mean drunk. He somehow managed to live for over a thousand years and mutated in that time to the extent that he's now just a head on a conjoined mutant offspring's shoulder. He is now a teacher.

Trivia

 * Andy is based off of of the underground mutant resistance leader, Kuato, from the sci-fi movie Total Recall, whose face emerges from another character's body. The difference is that Kuato a mutant living inside of / attached to a human, while Andy is a human living inside of / attached to a mutant.