The Guardian reported on Wednesday that the above photo is of a mug created by Colorado potter Tom Edwards, who was initially “thrilled” over having his work shared by Elon Musk.

What upset the 61-year-old artist was when the Tesla CEO—over-confident “inventor” of many a concept that no one needs and probably won’t materialize (probably because it already, ahem, exists)—tweeted out a copy of the farting unicorn image to promote Tesla’s “sketch pad” feature (“sketch” indeed). Subsequent articles appeared not to credit Edwards for the drawing.

The image later showed up as an icon in Tesla’s operating system and in the company Christmas card. Musk reportedly has not expressed interest in crediting Edwards or paying him for his work. “I love the fact that it’s in the cars, but I just want them to do the right thing and pay me adequately for it,” Edwards told The Guardian. “Elon Musk can be a hero for standing up for artists’ rights.”

On Wednesday, Musk responded to a tweet by Edward’s daughter, claiming the billionaire “ripped off my dad’s art.”

Suing for money is totally lame, right on, what a righteous titan of industry! And if it’s not his design why offer to change it? Highly suspect, Elon.

I can’t wait to find out what Grimes thinks about all this.