Battering Wurm

Oracle Text

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters the battlefield with a +1/+1 counter on it.)

Creatures with power less than Battering Wurm's power can't block it.

Card Rulings

2/1/2006 Battering Wurm compares each blocker’s power against its own as blockers are being declared.