Link 2 (As an additional cost to cast this creature, sacrifice two creatures you control with different names, except tokens.)

{2}, discard 1 creature spell: put X -1/-1 counters divided as you choose among any number of creature permanents, where X equals the discarded creature's converted mana cost.

If this face-up card leaves the field and goes to the graveyard, you can take 1 Alien creature, except Alien Shocktrooper Evolved, from your graveyard and put it onto the battlefield tapped.