Brain in a Jar is a rare Artifact card from Shadows over Innistrad Promos (PSOI), collector number 252s. Current market price: — (foil $1.36), TCGplayer market prices via Scryfall.
{1}, {T}: Put a charge counter on this artifact, then you may cast an instant or sorcery spell with mana value equal to the number of charge counters on this artifact from your hand without paying its mana cost. {3}, {T}, Remove X charge counters from this artifact: Scry X.