Xarial's Blinding Blade

You touch a melee weapon. Until the spell ends, the weapon’s blade is replaced with pure, searing light. The weapon becomes a magic weapon that grants a +1 bonus to attack and damage rolls, and it deals an extra 2d8 radiant damage on a hit. If the target is an aberration, it takes an extra 1d8 radiant damage, for a total of 3d8 radiant damage.

Additionally, when you hit a creature with an opportunity attack using this weapon, the target must make a Constitution saving throw against your spell save DC. On a failed save, the creature is blinded until the end of its next turn.