Nimon

The Nimons are a race of bull-headed humanoids from The Horns of Nimon.

The Nimons are large humanoids with the heads of bulls (somewhat like the minotaur of Earth). They have black skin, massive heads and large yellow horns. These horns can shoot out powerful blasts of energy. Of course, these energy blasts take a lot of energy, which the Nimons drain from their victims. After the draining, the victim is left as just a husk. The Nimons can use an artificial black hole as a gateway to another planet. This technology, though effective, is not energy efficient.

Due to their high energy needs, the Nimons need to continually move from planet to planet (which they call the The Great Journey of Life). Usually, one Nimon is sent to a planet, claiming it is a god with advanced technology. Once it's gained a supply of energy, it constructs a giant device to create a black hole. The Nimon then uses the black hole to get more Nimons to the planet. Eventually, all the Nimons are there and they drain the planet dry.

When the Doctor stopped the Nimon they were moving from Crinoth to Skonnos.