Doom Whisperer is a mythic Creature — Nightmare Demon card from Guilds of Ravnica Promos (PGRN), collector number 69p. Current market price: $6.48 (foil $11.79), TCGplayer market prices via Scryfall.
Flying, trample Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)