As a reaction, which you use when you make a Reflex saving throw or you are hit by an attack that you can see, you can shrink in size to avoid the attack. You make the roll with advantage or attacks against you are made with disadvantage until the start of your next turn, including the triggering attack. You can do so after the roll but before any effects of the roll occur.
If the roll already has advantage or disadvantage, you cannot apply another instance of advantage or disadvantage and you must use this before the roll to cancel out any advantage or disadvantage.
You can then move up to 2 meters without provoking opportunity attacks.
You can expend 1 additional mana to trigger the spell when you or one of your allies within 2 meters of you makes a Reflex saving throw or is hit by an attack that you can see. The attacked creature gains the benefits instead.