Crawler Turret

Sentry 1 (This creature can not attack or block and
when this creature's controller is attacked, defending
player may deal damage equal to this creature's power
to one target attacker.)
Unearth {b} (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.)