Astronomers have found two ultra-compact dwarf galaxies with supermassive black holes, the second and third such galaxies found to harbor the objects. Together, the three examples suggest that black holes lurk at the center of most ultra-compact dwarfs, potentially doubling the number of supermassive black holes known in the universe. The tiny galaxies were likely leftovers of larger galaxies stripped of their outer layers after colliding into other, larger galaxies.