Cockatrice Wood

This land enters the battlefield tapped.
{t}: Add {b} or {g}.
{x}, {t}, Sacrifice Cockatrice Wood: Add X
mana in any combination of colors to your mana
pool. Create a black and green 1/1 Cockatrice
creature token with deathtouch and "When this
creature deals combat damage to another
creature, you may return Cockatrice Wood from
your graveyard to your .. hand."