Wizard's Spellbook

{T}: Exile target instant or sorcery card from a graveyard. Roll a d20. Activate only as a sorcery. 1—9 | Copy that card. You may cast the copy. 10—19 | Copy that card. You may cast the copy by paying {1} rather than paying its mana cost. 20 | Copy each card exiled with this artifact. You may cast any number of the copies without paying their mana costs.