As an action, you set a trap in your mind against mental intruders. A creature who targets you with a spell or effect that would sense your emotions, read your thoughts, charm you, or force you to make a Will saving throw must make a Will saving throw.
On a failure, it takes 3d10 psychic damage and loses 1d6 mana if it has any mana.
On a critical failure, it takes twice as much damage.
On a success, it takes half as much damage.
On a critical success, it takes no damage.
The spell ends if you dismiss it on your turn (no action required) or if you cast it again.
You can increase the damage by 3d10 for each additional mana expended.