Arcane Reflection

When you're holding a melee weapon you're proficient with, and you or a creature within that weapon's reach is targeted by a spell attack, you may use you reaction to impose disadvantage on the attack roll.

If it is a ranged spell attack you may instead attempt to reflect the spell back at the caster or another target. Make a Ranged Spell Attack against the caster's Spell Attack roll. If it succeeds, the spell attack is reflected at a target of your choice within 30 feet and you use that same roll against the target's AC. If that hits then the target suffers the effects and damage of the triggering spell attack.

You may use this reaction after the attack roll, but before the damage is dealt.