Villain(s)  Alien creature

Actor(s):  Brian Donlevy, Richard Wordsworth, Jack Warner, David King-Wood

Brief Description  The Quatermass Xperiment (released as The Creeping Unknown in the US) is a seminal 1955 British science-fiction horror film produced by Hammer Film Productions. Directed by Val Guest, it is an adaptation of Nigel Kneale's highly popular 1953 BBC television serial. The film is widely considered a landmark in cinema history, as its massive success shifted Hammer's focus toward horror, effectively birthing the legendary "Hammer Horror" era.

Plot:
An experimental, single-stage-to-orbit rocket designed by Professor Bernard Quatermass crashes into the English countryside. Quatermass, local authorities, and the wives of the crew rush to the scene. The rocket had been launched into deep space with three astronauts aboard. When the specialized crew finally breaches the sealed capsule, they discover a baffling horror: only Victor Carroon is inside. He is alive but in a state of profound shock, completely catatonic and unable to speak. The other two astronauts, Reinfeld and Green, have completely vanished. A later investigation inside the completely sealed capsule reveals their space suits remain intact and securely buckled, yet their bodies are gone.

Carroon is placed under tight medical security at a hospital, overseen by Dr. Briscoe and Quatermass. Quatermass reviews automated film footage recovered from the rocket's cockpit. The footage reveals that mid-flight, an invisible, ethereal force penetrated the ship's hull. The crew members collapsed in agony as something entered their environment. Meanwhile, Carroon begins exhibiting terrifying biological changes. His skin becomes leathery, his behavior shifts to that of a cornered animal, and his right hand begins mutating into a swollen, misshapen mass embedded with alien, cactus-like spores. Quatermass deduces that Carroon was infected by an alien, parasitic entity. The entity did not just kill the other two crew members; it absorbed their biomass through Carroon, who is now gradually mutating into an entirely new alien organism.

Desperate to save her husband from Quatermass's cold scientific testing, Judith Carroon hires a private investigator to break Victor out of the hospital clinic. The escape goes horribly wrong. Upon seeing his wife, the barely human Victor flees into the London night, leaving a trail of death in his wake. Carroon realizes he needs organic matter to fuel his rapidly accelerating transformation. He wanders through London, visiting a zoo and slaughtering animals to absorb their biological tissue. He leaves behind completely drained, structurally dissolved carcasses. Scotland Yard's Inspector Lomax joins forces with Quatermass in a desperate race against time to track the creature before it reaches its final evolutionary form.

The entity—now a massive, tentacled, amorphous blob-like monster made of rubber, tripe, and alien vegetation—crawls into the scaffolding of Westminster Abbey, where the BBC is preparing a live television broadcast. Quatermass realizes the creature is on the verge of releasing millions of spores into the atmosphere. If it spawns, the alien lifeform will quickly engulf the Earth, destroying humanity. Acting quickly, Quatermass convinces London's power authorities to divert the city's entire electrical grid directly into the metal scaffolding of Westminster Abbey. The creature is struck by a massive surge of high-voltage electricity, incinerating it and saving the world just moments before reproduction occurs. As the ash settles, a grimly determined Quatermass walks out of the abbey, completely ignoring reporters to immediately start work on his next rocket project, Quatermass II.