Fear of the Unknown is a rare Enchantment Creature — Nightmare card from Unknown Event (UNK), collector number RC06b. Current market price: $15.00, TCGplayer market prices via Scryfall.
Trample When you cast this spell, choose a playtest card you own from outside the game. Exile it. You may cast that card as long as it remains exiled. Mana of any type can be spent to cast that spell. (In a sealed event, outside the game is your sideboard.)