Boneheap Predator

Whenever another creature you control dies
or is exiled from the battlefield, put a +1/+1 counter on Boneheap Predator.
Unearth {2}{b/r} ({2}{b/r}: Return this card from
your graveyard to the battlefield. It gains haste.
Exile it at the beginning of the next end step or
if it would leave the battlefield. Unearth only
as a sorcery.)