Skaratid

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

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