Mustard-based pizza is a thing and people are horrified

What's the biggest no-no topping when it comes to pizza? If you said pineapple, you'd be wrong.

Turns out, there's one even worse.

Papa's Tomato Pies in Trenton, New Jersey, created a concoction, which swaps out traditional tomato sauce for yellow mustard.

This pizza uses mustard instead of tomato sauce ? pic.twitter.com/XUKKQOBLwM

— FOOD INSIDER (@InsiderFood) September 4, 2018

According to co-owner Francis Garcia, the pizza came about after a drunk patron tried ordering a mushroom pie and was mistakenly heard as "mustard pie."

While some are claiming the unusual pizza is a hit, many aren't so enthused. One Twitter user even went so far as to say, "This should be illegal."

Can confirm: Mustard on pizza is great.

— PhillyCourtWatcher (@PhillyCtWatcher) September 6, 2018