Screwy Squirrel - The Screwy Truant (1945, animated short)

The Screwy Truant is a 1945 Screwy Squirrel cartoon directed by Tex Avery and released by MGM.
Screwy Squirrel (also known as Screwball Squirrel) is an animated cartoon character, an anthropomorphic squirrel created by Tex Avery for Metro-Goldwyn-Mayer. He is generally considered the wackiest and outright most antagonistic of the screwball cartoon characters of the 1940s.

Cameo:
Red and "Wolfie" (from Swing Shift Cinderella) make a cameo appearance. In the middle of the cartoon, the two interrupt one of Screwy's antics with the wolf chasing Red across the screen, only for Screwy to interrupt by showing the title of the cartoon, saying he is in the wrong cartoon. Swing Shift Cinderella wasn't released for another seven months, so it can be inferred that the script was being written at the time, and Tex wanted to give a short teaser for it.