That would be the Hive Warrior (Blue) and Acid (Brown) Aliens from the Hive Wars series, which consisted of six figures that initially were left unproduced, but were put out as a last ditch effort to revive the line (unsuccessfully), spurred on by fan support. The line also included a bionic Corp. Hicks, Integer 3, a synthetic, and two predators, one of which was a kind of PredAlien, although much more Pred than Alien.
