Heyvaaley

The Heyvaaley were intelligent light beings from another dimension. They travelled slower than light on Earth and had a mass capable of causing a trail of damage in their wakes. A Heyvaaley was in San Francisco in 1985. Before it was captured by the Eleventh Doctor, Amy Pond and Rory Williams, it had had taken on the persona of two arcade machine characters. It was trapped in the battery of a solar panel until it could be returned home. (DWA: Chasing Rainbows)