Marcus is Weird Harold's uncle from the episode, "Say Uncle."
Weird Harold, upset and complaining, he missed the movie he was gonna see with Fat Albert and the gang, mentioning that it's all because of his Uncle Marcus. As Harold arrives back home, His father informs him that Uncle Marcus is sharing his room with him. Harold and Marcus seem to have different taste in music, Mozart classic and a hippity-hoppity type.
- He is voiced by Lou Scheimer