The scariest thing a monster can do is not stay dead. That's exactly how the creatures in the Monstrous Surprise deck behave. When any creature with the undying ability dies, if it didn't have a +1/+1 counter on it, it returns from the graveyard to the battlefield with a +1/+1 counter on it. If it dies now, it'll stay down . . . but how many extra lives can your opponent afford to deal with?
Start out the game by developing your mana base with Rampant Growth and casting small creatures like Young Wolf and Strangleroot Geist. Eventually you can make your creatures more formidable in combat with Greatsword or Wild Hunger. Use Fling, Prey Upon, and Skirsdag Cultist's ability to take down your opponent's creatures (or your opponent!). Overrun and Pyreheart Wolf let you make a final push on the battlefield to win the game.