Family Guy: Season 12, Episode 2 - ProjectFreeTV

12 - 2: Vestigial Peter

Peter discovers that he has a vestigial twin, whom he names Chip, growing out of his neck. It's not long before Peter resents the fact that everyone seems to love Chip more than him, so he decides to amputate his twin. However, when Peter gets into trouble, he realizes he needs Chip more than ever.