As an action, a pillar of stone bursts from a place on the ground that you can see within 20 meters. A pillar is a cylinder. The ground where a pillar appears must be wide enough for its diameter.
A pillar has 12 Defense, 2 Soak, and 30 Health. When reduced to 0 health, a pillar crumbles into rubble, which creates an area of difficult terrain that is twice as wide as its normal radius that lasts until the rubble is cleared. Each 1-meter diameter portion of the area requires at least 1 minute to clear by hand.
If a pillar is created under a creature, that creature must make a Reflex saving throw or be lifted by the pillar. A creature can choose to fail the save.
On a success, the creature moves up to 1 meter to the nearest space.
If a pillar is prevented from reaching its full height because of a ceiling or other obstacle, a creature on the pillar takes 4d6 bludgeoning damage and is restrained, pinched between the pillar and the obstacle. A creature restrained by a pillar can use an action to make a Brawn or Nimbleness check (its choice) against your spell save Difficulty.
On a success, the creature is no longer restrained and must either move off the pillar or fall off it.
Augment
You can create one additional pillar for each additional mana expended.