Parasite from the Space
On the 5th Mission to the moon. A scientist cum astronaut gets infected with a mysterious ailment. After returning to the earth, Richard Barley shows strange sign of aggression and a taste for human flesh turning him into a very intelligent and aggressive cannibal. The parasites slowly spreads around the world infecting every part of the globe right from United States to India. But the major plot twist is that the the parasite has its own form of intelligence making it nearly impossible to be detected on any test or judging the infected behaviour. Thus making hidden among crowd.The parasite were specifically designed by an unknown entity to enslave and conquer inferior planets.