Kardur, Doomscourge 
Legendary Creature — Demon Berserker
When Kardur enters, until your next turn, creatures your opponents control attack each combat if able and attack a player other than you if able. Whenever an attacking creature dies, each opponent loses 1 life and you gain 1 life.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL