Thing (The Thing from Another World)

The Thing is a mysterious, highly-advanced sentient plant from an unidentified world.

Biology
On the outside, the Thing appears to be humanoid. However, it is presumably from a planet where plant life underwent a similar evolution to that of animals on Earth. As a result, its inner structure is far closer to that of plant life than animals. It reproduces via spores grown out of its hands, which are released, and its primary source of nourishment is blood from animals.

History
At some unidentified point, The Thing crashed onto Earth in a Flying Saucer. Over time the ship was frozen and the Thing itself was buried in a lake in the Arctic until it was discovered by a scientific research team who mistook it for an unidentified aircraft.

Accompanied by members of the U.S. air force, they discovered that their find was in fact a flying saucer. The attempt to unearth the ship was unsuccessful, but they found the Thing, cut it out, and brought it back to base. Unfortunately, as it happened, the Thing was accidentally thawed out and proceeded to start wreaking havoc on the men stationed there.

The Thing proved almost impossible to kill, as it could not be destroyed by flames or bullets, but was finally defeated when led into a trap containing concentrated electricity.