Dennis Coles, better known by his stage name Ghostface Killah, is a famous rapper from the Wu-Tang Clan. He appears solely in the episode "Stinkmeaner Strikes Back", as a ghost to Huey Freeman; despite the fact that, as Huey points out, he is not actually dead (neither in the series nor in real life, at the time that the episode aired).
Like the White Shadow, Ghostface Killah is similar to Huey's conscience, helping him when he is unsure in certain situations. He assisted Huey in facing the moral predicament of trying to fight Tom Dubois (possessed by the ghost of Colonel H. Stinkmeaner). Ghostface Killah reveals that the only way to help Tom and end the N***a Moment is by making peace with Stinkmeaner.