Riptide Pilferer is a uncommon Creature — Merfolk Rogue card from Time Spiral Remastered (TSR), collector number 83. Current market price: $0.15 (foil $0.39), TCGplayer market prices via Scryfall.
Whenever this creature deals combat damage to a player, that player discards a card. Morph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)