Spell Memory

Your ability to remember spells has enhanced your abilities to cast spells for the occasion. If you want to cast a spell that's not prepared, but is in your spellbook, you can make an arcana check. The DC equals 10 + the spell's level. On a success, the spell is cast (using the appropriate spell level slot). On a fail, the spell takes no effect, and the spell slot is wasted.

You cannot use this feat after you used it until after you took a long rest.