You're exploring a frozen planet devoid of life except for a small NPC village/research station and some hardier flora and fauna adapted to the cold. While mining, you uncover a creature, apparently dead, locked in a block of ice. It's unlike anything you've ever seen before, so you take it with you for further study. If at any point you expose the creature to heat, a small gooey bit melts off and tries to escape from you. The gooey bit will seek out the closest living being, kill it, and copy its shape. If you're close to the NPC village, it'll take over an NPC body...out in the wilderness...it'll copy a creature. If you don't find the creature within 5 minutes, it'll kill and copy another living being. When you do find the creature and attempt to kill it, it will respond like the creature it mimicked normally would...up to the point of death. Right before death it will mutate first into any other creatures it copied before, then finally into a mess of tentacles, spider arms, and teeth (final form). The longer it takes you to find the creature, the harder the fight will be. Leave the planet and when you return it may be devoid of life, except for one nightmare being able to transform into dozens of forms. Lose sight of it once , and you might have to wipe out life on the planet yourself just to make sure it has been eradicated.