Crystalline Entity

The Crystalline Entity was a massive, snowflake-shaped creature composed of a crystalline substance that used its powers of absorption to ravage hundreds of worlds throughout the Trek Galaxy. Its need to feed meant that it had to travel around the Galaxy, destroying all life on the planets that it attacks, in order to survive. Despite being responsible for the deaths of thousands of civilians, the Crystalline Entity was viewed more as a dangerous animal than an evil threat to the Galaxy, however, most Federation planets now contain defences that emit sonic emissions to ward off the creature when necessary.

The USS Enterprise has encountered the Crystalline Entity on several occasions, one of which was the first encounter with the Crystalline Entity by any Federation ship. Commander Data was recovered from a planet that was attacked by the Crystalline Entity, with Data being the only survivor since he is an android.