Hei Bai, Spirit of Balance 
Legendary Creature — Bear Spirit
Whenever Hei Bai enters or attacks, you may sacrifice another creature or artifact. If you do, put two +1/+1 counters on Hei Bai. When Hei Bai leaves the battlefield, put its counters on target creature you control.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyNOT LEGALvintageNOT LEGALcommanderNOT LEGAL