Overview
Destination Inner Space is a 1966 science fiction film produced by Earl Lyon, directed by Francis D. Lyon, written by Arthur C. Pierce, and stars Scott Brady, Gary Merrill, and Sheree North. The film was released to theaters in the US in May 1966 on a double bill with Frozen Alive (1964); its broadcasting rights were pre-sold to television so that some of the licensing fee could be used to finance the film's production. The story centers on scientists working in a laboratory on the floor of the ocean. They encounter an undersea flying saucer, after which the lab is attacked by a colorful aquatic humanoid monster who they fear may be the first in an alien invasion.
Plot
US Navy Commander Wayne has arrived at Topside, the support vessel for the civilian Institute of Marine Sciences' Sealab, a facility on the ocean floor. He is there because an unidentified object has been spotted circling Sealab. Cmdr. Wayne rides a diving bell down to Sealab, where he meets its director, Dr. LaSaltier and marine biologist Dr. Rene Peron.
During Cmdr. Wayne's arrival, a minisub carrying diver Hugh Maddox and photographer Sandra Welles is approaching the submerged object so as to get a clear photo of it. The object looks like a huge flying saucer, some 50 feet in diameter.
Inside the saucer, a little triangular door opens and a robotic arm pushes a cylinder encased in ice into the saucer's central area. A heat lamp hangs overhead. The ice begins to melt.
From Wikipedia (CC BY-SA 4.0).