Looney Tunes is a series of theatrical cartoons by Warner Bros.
In the WB cafeteria from Looney Tunes: Back in Action, animated versions of Scooby-Doo (voiced by Frank Welker) and Shaggy Rogers (voiced by Casey Kasem), argue with Matthew Lillard, who plays Shaggy in two live-action movies, about Lillard's movie performance. Animated!Shaggy threatens to come after Lillard if he performs similarly in Scooby-Doo 2: Monsters Unleashed.
Bugs Bunny and Daffy Duck appeared in Cartoon All-Stars to the Rescue, with the Smurfs. Even though Wile E. Coyote did not star in the special, he was mentioned by Bugs Bunny when he borrowed the coyote's time machine.