Sword of Feast and Famine is a mythic Artifact — Equipment card from Mirrodin Besieged (MBS), collector number 138. Current market price: $43.96 (foil $89.49), TCGplayer market prices via Scryfall.
Equipped creature gets +2/+2 and has protection from black and from green. Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control. Equip {2}