The Simpsons (1989)

S13E5 The Blunder Years

Homer deceives Marge into believing that an advertising spokesperson is set to visit, leading the family to a restaurant for the occasion. While there, a hypnotist puts Homer under his spell, unlocking a traumatic memory from his childhood when he stumbled upon a dead body in a ravine. Intrigued and disturbed, the Simpson family embarks on a quest to uncover the truth behind the mysterious corpse and its origins.