Slay the Undead Horde

Cast before you declare your attack. Target
Barbarian has rampage 2 and trample. All
black creatures that can block target must
do so. At end of turn put a +1/+1 counter
on target for every three black creatures
killed by target's combat damage this turn.
If this card is in your graveyard, you may
pay {g} and shuffle it into your library.