Mardu Ascendancy is a rare Enchantment card from Khans of Tarkir Promos (PKTK), collector number 185s. Current market price: — (foil $11.51), TCGplayer market prices via Scryfall.
Whenever a nontoken creature you control attacks, create a 1/1 red Goblin creature token that's tapped and attacking. Sacrifice this enchantment: Creatures you control get +0/+3 until end of turn.