Toy designer Skimbal has created a do-it-yourself kit that allows you to create your own Koopa shells from the greatest racing game ever in the history of the world: Mario Kart. Michael Curry ...

There, he stood atop a tilting giant Koopa shell inverted in a pool of lava. It was Mario's task to jump on him at just the right time, to send him sliding backwards into the molten magma.

Koopa Troopas are common, well-known enemies in the Mario series. Unlike Goombas, these guys can survive being jumped on. After being jumped on, however, they will retreat into their shell and ...