As two actions, the ground in a sphere centered on a point within 20 meters twists and sprouts hard spikes and thorns. The area becomes difficult terrain for the duration. When a creature moves into or within the area, it takes 1d4 piercing damage for every meter it travels.
The transformation of the ground is camouflaged to look natural. Any creature that can’t see the area at the time the spell is cast must make a Perception check against your spell save DC to recognize the terrain as hazardous before entering it.
You can increase the damage by 1d4 for each additional mana or psi expended.