Let alone not allowed on TER here, considering the beastiality in it, but off-beat humor nevertheless.  

Published on Jun 9, 2017

Eveready Harton in Buried Tresure is a 1929 sexy adult cartoon depicting the unlikely adventures of the perpetually aroused title character with a woman, a man, a donkey, and a cow.

Supposedly, U.S. film labs refused to process the film, and it had to be developed in Cuba. The artists are unknown, but a widespread rumor states that a group of famous animators created the film for a private party in honor of Winsor McCay.  

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. They didn't see the finished product till the night of the big show. A couple of guys who were there tell me the laughter almost blew the top off the hotel where they were screening it.

When a copy of the short was screened in San Francisco in the late 1970s, the program notes attributed the animation to George Stalling, George Canata, Rudy Zamora, Sr., and Walter Lantz. The short circulated informally, shown only at small underground festivals or parties, until 2002 when it was included in the theatrically released compilation The Good Old Naughty Days.