Iapetus is a crazy-ass moon! It bulges at the equator, squishes at the poles, and has an ancient equatorial ridge running around the dark part, rising up to 20 km above the rest of the surface; the moon has been described as "walnut-shaped." As is not surprising around a planet with such a huge ring system, Iapetus' surface is very heavily impact-scarred.
Is Iapetus Moon Of Saturn An Artificial Alien Construction? Watch video below