If it’s not your turn, you may exile a black card from your hand rather than pay this spell’s mana cost. Destroy all creatures that entered the battlefield this turn.
Obviously good against Vengevine, and potentially good against Token Makers+Shops+Dredge depending on their draws. I could see this having some impact.
Good one of in the sideboard.
Not as crazy as I was hoping the black one to be, but still a solid card for the sideboard I think. It's not too difficult to cast, and the main difficulty would be the black card density needed for the pitch cost.
It can also hose turns 1-2 of Aggro Shops.