Centaur Chieftain 
Creature — Centaur
Haste Threshold — As long as seven or more cards are in your graveyard, this creature has "When this creature enters, creatures you control get +1/+1 and gain trample until end of turn."
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL