The Bookworm

The Bookworm is a 1939 MGM cartoon directed by Hugh Harman and Friz Freleng.

Plot
Three witches need a worm to complete their potion; they dispatch a raven to catch one, and he goes after a bookworm. He chases the worm into the horror section, where the monsters attack but soon, Paul Revere rides Black Beauty to the rescue, along with the Police Gazette, and other assorted war heroes; eventually, the Boy Scouts build a match-stick bridge, leading the worm to safety.