Obelisk of Urd is a rare Artifact card from Magic 2015 (M15), collector number 222. Current market price: $3.17 (foil $8.49), TCGplayer market prices via Scryfall.
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) As this artifact enters, choose a creature type. Creatures you control of the chosen type get +2/+2.