Aqua Teen Hunger Force (2000)

S1E14 Dumber Days

Title: Dumber Days Plot: It is revealed that Meatwad's intellect is actually just a toy containing a jingle bell. Following a short spell of sadness, Carl decides to get Meatwad a new, functioning brain, despite Frylock's objections. With this upgraded brain, Meatwad starts to increase in both size and intelligence, leading to unexpected developments.