When Fat Albert and his friends go to the movie theater, there is a poster on the lobby wall for a movie called, "The Chicken Heart That Ate New York." This is a reference to one of Bill Cosby's early stand-up comedy routines, called "Chicken Heart," in which Cosby describes listening to the 1940's radio show, "Lights Out," as a child, and being scared to death by an episode featuring a giant chicken heart that ate New York City.
In some cuts of the Halloween Special, the movie playing at the theater is actually an episode of Space Academy (another Filmation production). The movie screen is never seen but the music and sound effects are clearly taken from that production.