As an action, your body becomes blurred, shifting and wavering to all who can see you. For the duration, any creature has disadvantage on attack rolls against you. An attacker is immune to this effect if it doesn’t rely on sight, as with blindsight, or can see through illusions, as with truesight.
You can expend 1 additional mana to cast the spell as a reaction, which you use when you are hit by an attack. The attacker must make an additional attack roll and use the worst result.