Elon Musk has made another promise on Twitter. The SpaceX founder and CEO took to the social networking site to answer questions and discuss his latest feat, the launch of the Falcon Heavy, and ended up promising to eat his hat.

Well, he’ll eat it under certain circumstances. First, with a side of mustard, and second, only “if that rocket flies a national security spacecraft before 2023,” he said about United Launch Alliance’s Vulcan Centaur rocket.

Eager spectators will have to wait a bit to see whether or not Musk will have to find a new way to cook up and season a hat. While it may seem like a bluff, Musk isn’t new to following through on the things he says he’ll do on Twitter. Musk seemingly joked about selling a flamethrower branded for his company, The Boring Company, but then to some of his followers surprise, he actually followed through.

Another one of the branded items Musk sold for his Boring Company was actually a hat, so he’s said that if it comes down to consuming a hat, it will be one of the hats bearing The Boring Company logo.

While answering questions he also revealed that the next droneship SpaceX will make will be called “A Shortfall of Gravitas,” this one will join “Of Course I Still Love You” and “Just Read the Instructions.” The ship will be used off of the East Coast of the United States to support launches of the Falcon 9 and Falcon Heavy rockets, he said.

Only time will tell whether or not ULA will be successful and Musk will be faced with the decision of breaking his promise or not.