Bloodsky Berserker 

Creature — Human Berserker
Whenever you cast your second spell each turn, put two +1/+1 counters on this creature. It gains menace until end of turn. (It can't be blocked except by two or more creatures.)
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL