Fortnite released the Season 2 Battle Pass in December of last year.
The game allows players who win to do the Floss.
In July this year, Fortnite developer Epic Games was estimated to be worth around $US8 billion ($NZ11.6 billion).
Just like Alfonso Ribeiro who sued Fortnite for stealing his dance "The Carlton" and the rapper 2 Milly, who sued Fortnite for using her dance the "Milly Rock" and using it as an emote, Horning says he's suing for intellectual property.
He says he was in the process of copyrighting the dance moves when the gaming giant stole "The Floss".
He's also suing 2K Sports, which makes NBA 2K, claiming that they also stole his dance.
But according to gossip website TMZ, Horning said in an interview in June that he did not expect royalties from Fortnite or even acknowledgment.
"It's not that big of a deal, I'm just glad it's in the game," Horning allegedly told the site.
But Horning appears to have changed his mind and is now represented by law firm Pierce Bainbridge Beck Price & Hecht.