Winter's Demonmech is a rare Artifact Creature — Horror card from Unknown Event (UNK), collector number RA05c.
You can't include this card in your deck if you're on Team Cloudspire. Flying Whenever this creature deals combat damage to a player, create a copy of one of the following, chosen at random: Early Winter, Plunge into Winter, Winterflame, Winter Sky, Winter's Grasp, or Winter's Intervention. You may cast the copy without paying its mana cost.