Madcap Experiment is a rare Sorcery card from Kaladesh (KLD), collector number 122. Current market price: $0.28 (foil $0.30), TCGplayer market prices via Scryfall.
Reveal cards from the top of your library until you reveal an artifact card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. Madcap Experiment deals damage to you equal to the number of cards revealed this way.