Aqua Teen Hunger Force - Season 1 Episode 14 -

After Shake uses Meatwad's brain to perform stunts in the pool, it's discovered that Meatwad's brain is nothing more than a toy with a jingle bell in it. After Meatwad goes through a brief depression, Carl gets him a new live brain against Frylock's will. After Meatwad gets his new brain, he begins to grow smarter and larger.