Wakko is dressed as the Hunchback as the name Lon Chaney is heard in the theme song
The grim reaper refers to Yakko, Wakko, and Dot as "nasty little Munchkins."
The hippos' neighbors (the rhinos) watch "The Price Is Right" on their TV set.
Yakko says "Guess who?" and The Grim Reaper says "That Urkel kid?" in reference to Urkel from this show.
"Meatballs or Consequences" is tied #7
The Warner Bros. play checkers with the grim reaper to try and win Wakko's soul back (he wants to play chess but they don't know how).