Arcane Appropriation

Whenever a creature within 60 ft of you casts a spell you can use your reaction to steal the spell for your own use. If the spell is one level lower than this one cast you immediately steal it, if it is above you must make a Charisma check (15 + spell level - level of spell this was cast at). Once you do so you have access to this spell as if you had it prepared for a number of hours equal to the double the level this was cast at.