Slithery Stalker is a uncommon Creature — Nightmare Horror card from Torment (TOR), collector number 84. Current market price: $0.26 (foil $4.10), TCGplayer market prices via Scryfall.
Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.) When this creature enters, exile target green or white creature an opponent controls. When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.