You conjure two small, magical shards of molten glass that circle around you. The shards appear in any color and pattern you wish. Until this spell ends, you can use your reaction to command a shard to hinder one melee attack against you. If you do so, that shard flies between you and your attacker and shatters, imposing disadvantage on the attack roll. If the attack hits you, the attacker takes 1d4 piercing damage. When all shards have shattered, the spell ends.    The spell conjures one additional shard when you reach 5th level (three shards), 11th level (four shards), and 17th level (five shards).