The gag comes from Fall Out Fall In, a Donald Duck cartoon released on 23 April 1943, where Donald endures a clumsy spell in the army and takes the kind of head knocks that make a bump rise under his helmet. The clip itself circulates as a Hollywood Edge library effect catalogued among various squeak and pop creaks, which helped stock cartoon sounds travel far beyond their first film. Editors still lift this tiny creak for retro animation edits because it instantly signals old school slapstick without needing dialogue or explanation.