Black Iron Tarkus

Whenever Tarkus becomes blocked you may pay {r}{g}. If you do, Tarkus gains +2/+4 and Trample until end of turn.
One of the longest surviving knights to attempt at curing undeath and fulfilling the prophecy, Tarkus defeated the Iron Golem. As the only one to prevail, he carved his summon sign for others to call upon him.