Rigged-Up Locust Reaver

Unnerving (This creature can't be blocked
except by creatures that are at least one more
card type, e.g., artifact or land creatures.)
First strike
Whenever Rigged-Up Locust Reaver attacks,
you may have it assign combat damage equal
to the mana value of the last card that was
put into defending player's graveyard rather
than its power.