Warning: The following contains SPOILERS for Masters of the Universe: Revelation, Part 2, episode 1, "Cleaved in Twain."
A throwaway line involving Skeletor in the premiere episode of Masters of the Universe: Revelation, Part 2 made reference to an infamous meme regarding the heroic warrior Fisto. This has effectively made the joke canon within the official Masters of the Universe setting. Given that the series' showrunner Kevin Smith is famous for sneaking adult references and puns into his films, there is almost no way that the line in question wasn't an intentional nod to the long-running fan joke.
Introduced as part of Wave 3 of the original Masters of the Universe toyline, Fisto was distinguished by his oversized metal fist. The original comics and cartoons never revealed if Fisto's fist was a gauntlet or a prosthetic, but the 2002 animated series established that his hand was cybernetic in origin and that he was the brother of Man-At-Arms. Fisto also appeared in a non-speaking cameo in one Masters of the Universe: Revelation Easter egg.
Fisto was promoted to a speaking role in Masters of the Universe: Revelation, Part 2, with his voice being provided by Ralph Garman, who co-hosts the Hollywood Babble-On podcast with Kevin Smith. Fisto was among the heroic warriors present when Skeletor projected his grim countenance over the city of Eternos, as dark clouds blocked the sun. This prompted Fisto to declare, as he raised his famous fist in anger, that "I'd sure like to fist him!"
While it was clear from the context that Fisto meant that he wanted to punch Skeletor, the word "fist" has an entirely different connotation, serving as a slang term for a certain sexual act. This has made Fisto into something of a joke among He-Man fans, with various memes and works of fan art being devoted towards Fisto and how he truly earned his name. The most famous of these involved an altered panel from the mini-comic "The Clash of Arms," where instead of an injured Fisto saying "I fought hard, He-Man, but I could not defeat them all," he appeared to say "I fisted hard, He-Man, but I could not fist them all!"
Fisto spoke of his desire to "fist" Skeletor in the Masters of the Universe: Revelation, Part 2 premiere, "Cleaved in Twain," which was co-written by Kevin Smith. While it cannot be said for certain that Smith was responsible for the knowing nod to the infamous meme, he certainly would have been responsible for letting the joke slide as the series' story editor. While the line was of questionable taste, it seems unlikely to spark further controversy for Masters of the Universe: Revelation.