The Balrog, Flame of Udûn 
Legendary Creature — Avatar Demon
Trample When a legendary creature an opponent controls dies, put The Balrog on the bottom of its owner's library.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL