Breach

About Breach: A hardened mechanic must stay awake and maintain an interstellar ark fleeing the dying planet Earth with a few thousand lucky souls on board... the last of humanity. Unfortunately, humans are not the only passengers. A shapeshifting alien creature has taken residence, its only goal is to kill as many people as possible. The crew must think quickly to stop this menace before it destroys mankind.

Deep in space they are not alone.