As two actions, squirming, ebony tentacles fill a sphere on the ground that you can see within 20 meters. For the duration, these tentacles turn the ground in the area into difficult terrain.
When a creature enters the affected area for the first time on a turn or starts its turn there, the creature must succeed on a Reflex saving throw or take 3d6 bludgeoning damage and be restrained by the tentacles until the spell ends. A creature that starts its turn in the area and is already restrained by the tentacles takes 3d6 bludgeoning damage.
A creature restrained by the tentacles or one that can touch the creature can use an action to make an Acrobatics or Brawn check (its choice) against your spell save DC.
On a success, the target is freed.
You can increase the damage by 1d6 for each additional mana or psi expended.