Parasite is a fictional mouse who appears in The Worker & Parasite Show alongside Worker. When Itchy and Scratchy left The Krusty the Clown Show, they got this cartoon instead. They were "Eastern Europe's favorite cat and mouse team."
All Parasite did in the cartoon was bounce about randomly to the music and mumble incoherently.
Behind the Laughter
Worker and Parasite also appeared in the Worker and Parasite! comic.