The Simpsons

Season 12, Episode 9

Episode Title: HOMЯ

Air Date: 2001-01-07

Overview:

While working as a human guinea pig (to pay off the family's lost savings after making a bad investment), Homer discovers the root cause of his subnormal intelligence: a crayon that was lodged in his brain ever since he was a boy. He decides to have it removed to increase his IQ, but discovers that being smart does not necessarily equal being happy.