Arcadroid

Hailing from the Nalva System, the Arcadroids are spherical aliens who can tuck their legs up and roll along the ground.

Fiction

The Transformers cartoon

A group of Arcadroids took part in the first Galactic Olympics on Athenia in the year 2005. Apparently, the bookmakers favoured them in the downhill events. Considering the stadium was completely flat, that didn't seem like much of an advantage. Five Faces of Darkness, Part 1