You know in EDH that your opponent has at least one creature they plan to play: their commander
Doing this also only costs two mana, which is quite powerful for Standards terms
The fact that two copies of Stoneforge Mystic were in the recent "War of Attrition" deck list almost stayed our hand from banning the card
Just like when you cast a ripple spell from your hand, the spell goes onto the stack, and then the ripple effect triggers and goes on top of it
Now, late game, the lameness evaporates and you have a mana sink that can be quite the beater
Eddie Brock / Venom, Lethal Protector The sacrifice outlet lives on Venom, Lethal Protector, which isnt good for decks interested in many sacrifice triggers but works well when youre focused on sacrificing creatures with high power