The Amazing World of Gumball (2011)

S4E18 The Wicked

Framed for giving squirrels nuts mixed with coffee and prune juice, Darwin sets out to convince Gumball that Mr. Robinson's wife, Margaret, has a kind heart hidden beneath her chaotic and sociopathic behavior. However, when Darwin witnesses Margaret's true malevolence, the two friends decide to expose her by catching her in the act of stealing a car.