Requires the Nemesis base game "You already know what it feels to be chewed by an Intruder? Do you know the feeling of what it is like to run from a Night Stalker through a Mars base? Do you want to know what it's like to be brainwashed by a Voidseeder? You are in the right place. This is a new Alien race with its own mechanics, new nightmare fuel monster miniatures, and a totally new experience. Compatible with Classic Nemesis, Aftermath and Lockdown."