Rupert is Stewie Griffin's teddy bear. In "The Quahog Crew" Rupert is almost food to Hamlet and Brian until Stewie shots them both with a blow dart causing them both to go to sleep. In "Black Friday", Tons of Ruperts are seen a shelf when the Martins go to The Crapstone Overstock Store.
S5E17 "Black Friday"
S6E17 "The Quahog Crew"