The Swarmlord 
Legendary Creature — Tyranid
Rapid Regeneration — The Swarmlord enters with two +1/+1 counters on it for each time you've cast your commander from the command zone this game. Xenos Cunning — Whenever a creature you control with a counter on it dies, draw a card.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL