Undergrowth Reaver

Deathtouch, Trample
As an additional cost to summon Undergrowth
Reaver, sacrifice a creature.
{4}{g}{g}: Undergrowth Reaver becomes
unblockable until end of turn.
Enrage - Whenever Undergrowth Reaver is dealt damage, sacrifice target creature you control and destroy target creature with toughness X or lower
where X is equal to the sacrificed creatures
converted mana cost.