Avalanche Ambush

Create a 3/3 red Yeti creature token with
haste.
Spellcraft 1 - {2}{r}{r}, Sacrifice a land:
Whenever a nontoken creature enters the battlefield. (You may cast this card for its spellcrafting cost. If you do, exile it as it resolves. Cast a copy of this spell next time a nontoken creature enters the battlefield.)