Hour of Reckoning
Sorcery
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature’s color.)
Destroy all nontoken creatures.
"What in Frog's name is that sir?"
"I don't know Toadie, but it ain't good."
—Toadie and Mayor Toadstool
People use it as a combat trick to always kill a blocker
Or
Use this on their big creature to swing in and win.
I'd say make this cost 1R, just to be on the safe side. There's also a shocking amount of haste in the set, which might concerning for future balancing.