Skyclave Apparition is a rare Creature — Kor Spirit card from Mystery Booster 2 (MB2), collector number 18. Current market price: $0.37, TCGplayer market prices via Scryfall.
When this creature enters, exile up to one target nonland, nontoken permanent you don't control with mana value 4 or less. When this creature leaves the battlefield, the exiled card's owner creates an X/X blue Illusion creature token, where X is the mana value of the exiled card.