Skaratid

The Skaratid was a large green one eyed creature with five mouths two legs and two tentacled arms. On some worlds the young are kept as pets until they grow up to savage carnivores.

Shipped around the galaxy one was left on Earth, California in the 19th century where it took to living underground in one of the many mines that were set up in the search for gold. It had scared off all the other prospectors (except Ike who continued to mine in the upper levels, until the arrival of the Doctor, Amy Pond and Rory Williams who killed it by using its insatiable appetite against it to consume live sticks of dynamite.(DWAM: Mine, All Mine!)