Snarlfang Vermin 
Creature — Rat
Whenever Snarlfang Vermin deals combat damage to a creature, if that creature is still on the battlefield, suspect that creature. It perpetually gains this ability. Whenever a suspected creature an opponent controls dies while Snarlfang Vermin is in your graveyard, that opponent loses 1 life.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyNOT LEGALvintageNOT LEGALcommanderNOT LEGAL