The future isn’t now, but it is tomorrow.

October 21, 2015 marks Back To The Future Day. It’s the day that Marty McFly and Doc Brown time traveled to in their flux capacitor-equipped DeLorean in the iconic 1989 film Back To The Future II. It’s also the rare holiday that only happens once (at least until time travel becomes more a real thing), so it provides a great opportunity to look back at all the important ways that the movie impacted our lives, from giving us hoverboards to predicting 9/11.

For sneakerheads, Back To The Future II also gave birth to the Nike Air Mag with its power lacing system. The shoe has holy grail status, and in 2011, Nike auctioned off 1,500 versions of the Air Mag on eBay to support the Michael J. Fox Foundation for Parkinson’s Disease research. The most expensive pair went for $37,500. That’s an investment you’d want to protect.

To show off how its Crep Protect sneaker spray works, the brand created the video above in which a Marty McFly lookalike arrives in a DeLorean only to have his Nike Air Mag sneakers doused in ketchup. Fortunately the spray does its job and the ketchup is easily rinsed away.

Nike designer Tinker Hatfield, who worked with the filmmakers to create the shoes used in the movie, hinted that Nike might release a new edition of the Air Mag this year, but no other details have emerged since. So if you already own a pair, it might be a good idea to protect them before you eat french fries again.

Justin Tejada is a writer and editor based in New York City. Follow him on Twitter at @just_tejada.