Created anonymously by a group of professional animators in about 1929, the silent short Eveready Harton in Buried Treasure is a gleeful exploration of the penetrative arts. The four-and-a-half-minute short follows the travails of the uncomfortably well-endowed title character as he wanders a barren landscape in search of satisfaction. Along the way, he encounters a self-pleasuring maiden, various sexually aroused animals, a surprised husband, and a donkey-humping farmer, whom Harton challenges to a duel. A penis duel.
Eveready Harton in Buried Treasure is one of the earliest examples of an animated porn film. According to its Wikipedia page, several famous animators supposedly made the short for a private party in honor of the pioneering animator Winsor McCay, whose work greatly influenced Walt Disney and is still held in high esteem by Maurice Sendak, Chris Ware, and other luminaries.
This totally isn’t safe for work, so be careful.
I’m pretty sure the intertitles in this copy are not the originals.
The Wikipedia page includes this backstory quote from Disney animator Ward Kimball: “The first porno-cartoon was made in New York. It was called ‘Eveready Harton’ and was made in the late 20’s, silent, of course—by three studios. Each one did a section of it without telling the other studios what they were doing. Studio A finished the first part and gave the last drawing to Studio B. ... Involved were Max Fleischer, Paul Terry and the Mutt and Jeff studio. ... A couple of guys who were there [at the party] tell me the laughter almost blew the top off the hotel where they were screening it.”