As unorthodox a shoe as there's ever been, the Nike Mag can present a few challenges for those trying to find the right fit. That was especially true in 1989, when Michael J. Fox was fitted for the movie prop sneaker that would go on to become one of the all-time iconic sneaker silhouettes. To get the actor auto-laced up for the film, a shoemaker prepared a wooden last modeled after Fox's foot — which is somehow available to purchase.

The left foot last, in Fox's size 7/D, was completed in Feb. 1989, which indicates an extremely quick turnaround for what would become the prop shoes. Hand-drawn calligraphy along the lateral side reads "M.J. Fox Anatomical," marking the shoe for Fox. According to the owner, a former Nike employee who worked on the Mag, the remaining lasts were destroyed in fire, likely making this the only one in existence.

This insanely rare sneaker artifact is actually available for bidding on eBay. Bidding, which starts at $5,000, closes early Monday morning.

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