Voracious Wurm

Digest (Whenever this creature kills another creature,
exile it and put a +1/+1 counter on this creature.)
{5}, {t}: Voracious Wurm fights target creature
with power less than Voracious Wurm's
toughness.
If I'm gonna die, please let it not be by one of those
things.
-Daveon, Shiv Lavamage