Chryssalid

The Chryssalid is a dangerous alien monster used as an effective terror weapon by the Snakemen in X-Com: UFO Defense(Enemy Unknown). It resembles a giant crab with a black shell, huge claws, two antennae on its back and a mouth that appears to be in a permanent wicked smile. The creature's primary attack is what makes this alien one of the most feared and hated alien species in X-Com. It attacks a human, civilian or soldier, with a poisonous bite that turns the victim into a mindless zombie. Then it impregnates the victim with a Chryssalid embryo. Killing the said zombie would cause the Chryssalid to burst out of the host's body.