Proteus Staff is a rare Artifact card from Mirrodin (MRD), collector number 230. Current market price: $3.61 (foil $32.16), TCGplayer market prices via Scryfall.
{2}{U}, {T}: Put target creature on the bottom of its owner's library. That creature's controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield and the rest on the bottom of their library in any order. Activate only as a sorcery.