Arthur is the secondary antagonist of the Fat Albert movie. He is Reggie's absent minded partner in crime; he does not know how to handshake and when Reggie made a run for it he did the same thing.
He and Reggie laugh at Fat Albert for having to drink at a different water fountain.
He then Arthur saw that Fat Albert was a good singer and then he tried with Reggie to tell everyone that Fat Albert's a cartoon and then when he saw that Fat Albert grabbed Reggie by the shirt and consumed him.