Snoww, Unlight of Dark World

If this card is discarded to the Graveyard by a card effect: If it was discarded from your hand to your Graveyard by an opponent's card effect, you can target 1 monster in your opponent's Graveyard; add 1 "Dark World" card from your Deck to your hand, then Special Summon that target (if any) in face-up Defense Position.