X the Unknown

The increased radiation background at one of the military bases in Scotland attracts an unknown underground life form to the surface, which leaves behind two soldiers' corpses and a bottomless hole in the ground. Eyewitnesses claim that the unknown creature absorbs radiation, as a result of which it increases in size.

This thing is sent to the Lohmut Atomic Energy Laboratory to get the cobalt used there. The inhabitants of Lochmut hide in the chapel when the monster approaches them. The creature makes a raid on a nuclear facility before the authorities manage to remove the radioactive cobalt to a safe distance. As a result, the creature becomes even bigger.

Scientists are achieving some success in developing an anti-radiation device. During the experiment, it neutralizes a small container with radioactive material – however, the container explodes at the same time. Having no time for further experiments or safety considerations, scientists install two similar large devices on trucks and use a canister of cobalt, trying to lure the monster out of the crack in which he hid. The plan works: the creature is neutralized and explodes at a sufficiently large distance from the observers, which allows them to avoid injury.

When the team approaches the crack from which the monster emerged, a second, more powerful explosion suddenly occurs, knocking several people off their feet, but generally leaving them unharmed. Puzzled scientists continue to approach the crack – presumably for further testing... This is where the film comes to an end.