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 Wizard's
Spellbook. You may cast any number of the
copies without paying their mana costs.