Wu-Tang members Ghostface Killah and Cappadonna were spotting performing at a White Castle in the Bushwick neighborhood of Brooklyn last night (April 11).

While may assume performing at the fast-food chain is a sign of hard times for the rapper, it turns out he was there to celebrate the Impossible Burger’s arrival at the burger joint. Questlove also performed at the venue.

For the first time in its 97-year existence, White Castle is now vegetarian-friendly. It joins the ranks of other fast food restaurants like Burger King by serving veggie patties. The Impossible Burger is a plant-based patty that resembles meat and appears to bleed like actual flesh. However, the patty is made up of potato, wheat protein, and the blood is heme a plant-derived compound.

In a snippet of the performance uploaded by Ghostface to his Instagram account, you see him and Cap performing “Da Mystery of Chessboxin’” with DJ Klay Slay and Questlove in the background.

As reported by USA Today, White Castle’s Impossible Sliders will be made with the Impossible Burger Patties. They will arrive at over 1,000 location and will be served with smoked cheddar, pickles, and onions. The chain will see the burgers at $1.99 a significant price increase as a beef sliced is well under one dollar. The veggie slider will also be double the size of a regular White Castle slider.