Buck Knife Joe is the replacement for Steve in Roger's improv group in "The Sinister Fate!!".
When Roger becomes paranoid that the members of his improv troupe want to kick him out, he manages to steal the group away from them and auditions Steve and his friends to replace them. But when they begin to show any sign of talent that could surpass his, he gets rid of them and replaces them with vagrants until the entire group is replaced. As they start to perform their show in front of an audience consisting of mostly Steve and his friends, the vagrants remove their masks and reveal they are the original members of the troupe that Roger deposed, turning the tables and kicking him out of the group.