The Master, Mesmerist is a rare Legendary Creature — Time Lord Rogue card from Doctor Who (WHO), collector number 428. Current market price: $0.31 (foil $0.41), TCGplayer market prices via Scryfall.
{T}: Target creature an opponent controls with power less than or equal to The Master's power gains skulk until end of turn. Goad it. (A creature with skulk can't be blocked by creatures with greater power.) Whenever a creature with skulk deals combat damage to one of your opponents, put a +1/+1 counter on The Master and draw a card.