Invader Spleen, seen in The Nightmare Begins, was the second Invader called forth in Operation Impending Doom II's Great Assigning to get an enemy planet, where he impressed the Tallest with his height. In episode Hobo 13, he was seen again sitting at a table nearest Almighty Tallest Purple, but was only seen in background shots. Much like Invader Chin, Spleen is named after a human body part.