Arcane Mirror

Upon casting this spell, you become protected by an arcane mirror. When the caster is targeted by a spell using a spell slot lower than the slot used to cast this that targets just the caster (such as guiding bolt, but not fireball), the spell is reflected back at the attacker using the same attack roll/spell save. 

The spell lasts for 1 minute, until you lose concentration, or until you are hit by a spell of a higher level than the casting of this spell.