The Nike "Slamball Sneakers"

The original BTF2 shoes for the movie were designed by Tinker Hatfield and
built by hand in the Nike Sample Room. The lights in the side of the midsole
and the Nike logo on the ankle strap were electro-luminescent panels. There also was an array of six randomly flashing LEDs on the side of the heel that were never visible in the movie. Originally they were called “Slamball Shoes,” and that’s what most people called them around Nike. There was supposed to have been a scene in the movie in which Marty plays Slamball, a game like 3D racquetball where the participants wear magnetic shoes which allow them to climb up the walls.
That scene was never shot because the cost of building a huge room on
gimbals to create the effect was too great. The REAL name of the shoes in Marty McFly’s world of 2015 was the “Nike Mag” because of their magnetic properties, and that’s what is molded in the back of the heel.