Hyperion is one of the largest irregularly shaped objects in the solar system. In fact it was the first non-round moon to be discovered. Hyperion is a moon of the giant ringed planet Saturn. It was discovered on September 16th 1848 by William Bond, George Bond and William Lassells.
Hyperion is 255 by 163 by 137 miles in size, the moon spins approximately once every 13 days on its 21-day trip around the planet. However, its odd shape keeps it from a predictable rotation.