As two actions, a fountain of molten lava erupts from a point on the ground within 20 meters. Each creature in a cylinder centered on that point must make a Reflex saving throw.
On a failed save, a creature takes 6d6 fire damage and is burning 2.
On a successful save, a creature takes half as much damage and doesn’t start burning.
Additionally, the ground in that area becomes difficult terrain until cleared. Each 1-meter square portion of the area requires at least 1 minute to clear by hand.
You can increase the damage by 2d6 and the burning level by 1 for each additional mana or psi expended.