Taj-Nar Swordsmith is a uncommon Creature — Cat Soldier card from Modern Masters 2015 (MM2), collector number 36. Current market price: $0.11 (foil $0.48), TCGplayer market prices via Scryfall.
When this creature enters, you may pay {X}. If you do, search your library for an Equipment card with mana value X or less, put that card onto the battlefield, then shuffle.