The Sea Devils

The Sea Devils was the name given by humans to an intelligent lizard-like amphibious life form related to the Silurians.  Fearing global destruction from the body which became Earth's moon, they retreated into underground shelters, where they overslept for millions of years whilst their supremacy over the Earth was eclipsed by man. Woken by drilling operations, a colony of Sea Devils armed with hand guns and aided by the Master to set about reclaiming the Earth from the humans (The Sea Devils). In a second attempt to rid the Earth of mankind, another colony of Sea Devil warriors was revived on Sea Base Four (an underwater military installation equipped with nuclear weapons, one of many maintaining the balance of power in Earth's future, was attacked from two unrelated sources. An internal threat was posed and the external one from the Sea Devils and Silurians). As their previous encounter, the Doctor was responsible for the annihilation (Warriors of The Deep).