10199 Chariklo is the largest known Centaur (minor planets orbiting between the orbits of Jupiter and Neptune), and currently the only known rocky body in the solar system to have a set of rings.
Included in this add-on, is a small hypothetical shepherd moon orbiting just outside the outermost ring of Chariklo. While the existence of a shepherd moon/moons hasn't been proven yet, it is highly likely based on the geometry and state of Chariklo's rings that there is at least one moon, and the properties of the hypothetical moon has been designed to be consistent with those rings.