Phillip Williams is taking the national fast food chain Burger King to court for cooking their new meatless sandwich on a shared grill with actual meat.

The Georgia man is working on a class action lawsuit against Burger King for himself and “similarly situated individuals,” who consumed the supposedly vegan-friendly burgers after they were cooked on the same grill as the regular ones — “covering the outside of the Impossible Whopper’s meat-free patties with meat by-product.”

Despite its target demographic, Burger King states on its official website that the sandwich also contains non-vegan mayonnaise. Should a customer desire a truly vegan meal, the company suggests they specify that their burger be prepared with a “non-broiler method.”

Williams contends that the information was not clearly posted at the location he visited and that he was led to believe the sandwich — ordered without the aforementioned mayo — would be truly meat-free. Burger King, as expected, has refused to “comment on pending litigation.”

Lawyering aside, the “Impossible Whopper” has been a massive success for the franchise. Parent company Restaurant Brands International (RBI) called it a “huge hit.” RBI CEO José Cil reported a half-billion improvement over last year’s performance, with the “0% beef” patties driving as much as five percent of their sales growth.