Heelys brand sneakers function as ordinary street shoes, but include the hidden feature of embedded wheels that the user can activate by shifting weight to the heel. Introduced in the year 2000, the novelty shoes became a millions-selling fad among children worldwide.

Available in child and adult sizes, Heelys are not quite as versatile as they may appear to the uninitiated. The wheels do not pop out of the heel at the will of the wearer, but are actually always activated. This requires the user to walk differently when not rolling, with slightly greater pressure on the ball of the foot than normal. The wheel can be removed in order to transform Heelys into standard walking shoes.