Swarm of Bloodflies 
Creature — Insect
Flying This creature enters with two +1/+1 counters on it. Whenever another creature dies, put a +1/+1 counter on this creature.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL