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Private SNAFU: Booby Traps (1944) is a four-minute cartoon that the U.S. Army Signal Corps made for its own soldiers. It is one of 26 Private SNAFU cartoons ("Situation Normal, All Fouled Up"), made to educate the troops and lift their morale. According to the archive.org description, the series was originally created by Theodor Geisel (Dr. Seuss) and Phil Eastman, and most of the cartoons were produced by Warner Bros. animation, using its animators, voice actors (mainly Mel Blanc) and Carl Stalling's music. The archive.org item credits Robert Clampett as the creator of this one.

The lesson is on the soundtrack before anything happens. A narrator says the enemy has fled and the area is abandoned, then warns that "as our forces move up, they must exercise great care" (00:13). "Every object is a possible booby trap" (00:18), he says, and "if you are a boob, you will be trapped" (00:28). Private Snafu answers with "I ain't no boob and I won't be trapped" (00:35).

Then the film shows what it means. A sign offers free camel's milk, and under the camel hangs a spiked black ball where an udder should be. A pin-up whose flower pasties turn into two black bombs sits beside him, and Snafu sings that something new has been added (03:01). A piano is wired to a drum marked TNT, and a finger presses a key. The film ends on Snafu as an angel on a cloud with a halo and a harp, saying "...at least up here" (04:03) that he has nothing to worry about.

What makes it strange now is how much was hidden behind it. Only soldiers were ever meant to see these cartoons: the Army kept them secret and treated the films as classified. The staff who worked on them had to pass an FBI check and give their fingerprints, and the painters were handed just ten cels at a time, so none of them could piece the story together. They never had to go before Hollywood's censors at the Production Code Administration, which is how a 1944 cartoon got away with a pin-up like this one. Even the hero's name is Army slang with a swear word inside it (SNAFU: "Situation Normal: All F***ed Up"), and Booby Traps is one of six Snafu shorts in which he dies.

The joke outlived the war. Seven years later, in Ballot Box Bunny (1951), Yosemite Sam booby-traps a piano for Bugs Bunny on the tune "Those Endearing Young Charms" and ends up blowing himself up; Wikipedia records that Warner Bros. took the gag from a Private Snafu short. The sheet music on Snafu's piano here reads "Believe me if all those endearing young charms". Snafu even sounds like Bugs: Mel Blanc voiced them both.