Episode 41 of "Futurama"
s03e12 Insane in The Mainframe

Fry and Bender are arrested for bank robbery when they get involved with one of Bender's old robot friends, Roberto, while he's robbing a bank. Fry and Bender are convicted of the crime and sent to an asylum for criminally insane robots. It's a walk in the park for Bender, but Fry is tortured by being treated like a robot. When Fry is finally brain-washed into believing he is a robot, he is deemed "cured" and released. His friends back at Planet Express are horrified when Fry the robot is returned to them. Meanwhile, Roberto is busted robbing the same bank again and ends up in the asylum with Bender. He uses Bender to bust out of the asylum and accompanies his friend back to Planet Express. When the police track them down, Roberto takes the staff of Planet Express hostage. Fry turns into a battle droid and scares the mentally unstable Roberto so badly that he jumps to his death. In the battle, Fry's arm is injured, and when he sees that he bleeds blood he comes to his senses and realizes he's a human.