Peanut Butter Kid (also known as "Sandwich Boy") is a younger student who appears in the episode "The Kid Came Back." (And in "King Gus" before that). He is the false antagonist of that episode, but it turns out that the real antagonist is (instead of any character) only their bad luck that just happens. He follows the main characters around for most of the episode and seems to bring them bad luck, but because despite him eventually being sent away, bad luck continues, it turns out their bad luck isn't his fault. He is always seen eating a peanut butter sandwich because his mother forbids him to eat sugar foods.
He is impossible to get rid of without telling to go away and can move at implausible speeds, as he was able to instantly reappear near the gang despite being sent across the city, the state, or even China (even having time to get a Chinese-style sun hat).
His only speaking role was in "King Gus", in which he gets sentenced to hard labor for being unable to pay Gus' cookie tax. He is voiced by Ryan O'Donohue. He has also appeared in many episodes as a background character