Umbris, Fear Manifest is a mythic Legendary Creature — Nightmare Horror card from Crimson Vow Commander (VOC), collector number 38. Current market price: $12.20, TCGplayer market prices via Scryfall.
Umbris gets +1/+1 for each card your opponents own in exile. Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land card.