Certain Death
Oracle Text
Destroy target creature. Its controller loses 2 life and you gain 2 life.
Card Rulings
7/13/2016 The targeted creature will have already left the battlefield before its controller loses 2 life and you gain 2 life. If it has any abilities that care about gaining or losing life, they won’t apply.
7/13/2016 If the creature becomes an illegal target for Certain Death, no player gains or loses life. If it’s a legal target but isn’t destroyed, most likely due to having indestructible, its controller still loses 2 life and you gain 2 life.
that said, this card looks like this sets sip of hemlock, only slightly better in a vacuum. Might be necessary against big emerge cards even if many (all?) provide value on etb, preventing the actual 2-4-1.