Spell-stealing spellbook page

When this card enters the battlefield, If you control a spellbook, gain {U}{U}{U}{U} and draw a card. Whenever an opponent casts an instant or sorcery spell, instead of putting it in their graveyard, they exile it instead. {6}, {t}: Cast all instant or sorcery spells exiled with this card, then gain forbidden counters equal to twice the amount of spells cast in this way. (if a player has 27 or more forbidden counters, they lose the game.){flavor}HA! I stole your ca-ards! now I can cast them!