Heyvaaley

The Heyvaaley are an intelligent light being from another dimension that travel slower moving than light on Earth with a mass capable of causing a trail of damage in its wake. One such creature was around in San Francisco in 1985 where before being captured by the Doctor, Amy Pond and Rory Williams it had had taken on the persona of two arcade machine characters before being stopped and trapped in the battery of a solar panel until it could be returned home. (DWAM: Chasing Rainbows)