Blighted Blackthorn is a common Creature — Treefolk Warlock card from Lorwyn Eclipsed (ECL), collector number 90. Current market price: $0.14 (foil $0.28), TCGplayer market prices via Scryfall.
Whenever this creature enters or attacks, you may blight 2. If you do, you draw a card and lose 1 life. (To blight 2, put two -1/-1 counters on a creature you control.)