Space Ghost welcomes shiny happy Michael Stipe from R.E.M. (Space Ghost: "Is that you in the corner?"Stipe: "Yes, it is.") Later, he shares time-honored difficult-places-to-reach-while-scratching-stories with Lassie. Mujibur and Sirajul, frequent guest stars on "The Late Show with David Letterman,"mysteriously appear with Space Ghost's pizza.