Voyage to the Bottom of the Sea Season 3 Episode 1
Seaview is investigating a thousand-mile wide communication blackout. The source of this is a large alien brain found under the sea. It is broght aboard and takes over visiting scientist, Dr. Lindsay. With his help, and after possessing Captain Crane, the alien vows to take over the Seaview and after that, the Earth.
Episode Title: Monster from the Inferno
Air Date: 1966-09-18