Pretty much every major character in the mythos of Magic: the Gathering has had some sort of artwork. One of the last major holdouts was the game's longtime villain and human/god Yawgmoth, wasn't even seen until Dominaria's Yawgmoth's Vile Offering in 2018, with a creature card only just coming out that following year with Modern Horizons' Yawgmoth, Thran Physician.
Early on in the game's history, however, everyone thought that Yawgmoth was a rather rastafarian-looking demon. And why is that? Miscommunication and misleading title mostly.
Fans immediately latched onto the idea that the creature presented in the card's art was a demon named Yawgmoth. The argument repeated itself a number of years later when the card was reprinted in Ninth Edition.
To add to the confusion, a June of 2001 issue of the InQuest Gamer magazine posted artwork of Yawgmoth that looked strikingly different than that found on Yawgmoth Demon or any of the other then-published Yawgmoth cards such as Yawgmoth's Bargain, Yawgmoth's Will, and so on. The magazine even included a caption that refers to Yawgmoth as an "unstable shapeshifter."
For the most part, Wizards of the Coast stayed silent on this topic until speculation grew to such a point that they just HAD to answer. And the prognosis? Uh, well, sure.
In 2008, they pretty much said in a Q&A section that the Demon was indeed Yawgmoth. And that kind of satisfied people...until it was revealed that they had given a wrong answer.
Specifically this: "At first, I wasn't sure whether Yawgmoth Demon was the Yawgmoth, or maybe just "a demon of Yawgmoth". But here's the art description for the Ninth Edition version, which seems to settle the question pretty definitively:
'Show Yawgmoth, who is an enormous flying abomination of Phyrexian origin (a necro-tech setting). It should have two horns and wings, but the rest is up to you. Should be a horrifying flesh/metal hybrid.'
"So there you go! Note that this doesn't mean that Yawgmoth's full name is "Yawgmoth Demon". He's not related to Maxwell Demon, the on-stage persona of Brian Slade in Todd Haynes's glam rock movie Velvet Goldmine, is what I'm trying to say."
With not even WotC seemingly able to get the story straight, the next decade would seem to bring even confusion. In fact, the answer provided in the 2008 Q&A was retracted due to it being simply incorrect.
Then came Dominaria and that Yawgmoth's Vile Offering card, which features artwork that not only shows an extremely pivotal scene in the Invasion storyline wherein Gerrard has decapitated Urza in the Phyrexian Arena, but also shows an all-powerful and deified Lord of the Wastes in the background. It turns out that Yawgmoth's Demon really was just a demon of Yawgmoth's creation and that Yawgmoth, by the time of the Phyrexian Invasion of Dominaria, was a monstrous perversion of his original human form during the ancient time of the Thran.