Fifth Column Mouse (Cartoon, 1943)

The Fifth-Column Mouse (also stylized as The Fifth-Column Mouse) is a 1943 Merrie Melodies animated short produced by Warner Bros. Cartoons and directed by Friz Freleng. Running approximately 7 minutes, it is a wartime propaganda cartoon that uses anthropomorphic animals to satirize World War II themes, particularly the dangers of appeasement and betrayal by "fifth columnists" (traitors or collaborators within a group).
The story begins with a cheerful group of mice enjoying leisurely water sports in a kitchen sink, singing a playful rendition of "Ain't We Got Fun." Their idyllic fun is interrupted by a lurking black-and-white cat, who cunningly approaches a dim-witted grey mouse (resembling a rat) and bribes him with promises of unlimited cheese in exchange for convincing the other mice to submit as the cat's slaves. The gullible grey mouse spreads the message of appeasement, leading the mice to initially disarm and trust the cat during a tense meeting underscored by a parody of "Blues in the Night."However, the cat's true intentions soon reveal themselves—he plans to devour the mice. The grey mouse, realizing his mistake, repents and rallies the group to unite against the threat. The mice mobilize for war, forming a miniature army with makeshift weapons and vehicles. In a climactic battle, they launch a fierce counterattack using a battleship modeled after a bulldog, ultimately defeating the cat by chasing him down and shaving him bald with an electric razor (leaving tufts of fur that form a "V" for victory in Morse code). The mice celebrate their triumph by marching and singing "We Did It Before (And We Can Do It Again)," but they comically punish the grey mouse for his earlier betrayal by smashing a cream pie in his face as he exclaims, "We dood it!"