Cognac Mama-Mash (OP11-081) - A Fist of Divine Speed

[Main] Choose a cost and reveal 1 card from the top of your opponent's deck. If the revealed card has the chosen cost, K.O. up to 1 of your opponent's Characters with a base cost of 8 or less.
[Trigger] Add up to 1 DON!! card from your DON!! deck and set it as active.