concentration, 1 minute/mana
As two actions, small fissures continuously open and close on the ground in a sphere centered on a point within 20 meters for the duration. The fissures turn the ground into difficult terrain for the duration.
A creature that enters the spell’s area for the first time on a turn or starts its turn there must make a Reflex saving throw.
On a failure, it takes 3d8 bludgeoning damage and is knocked prone.
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.
At the start of each of your turns if the fissures are within 20 meters of you, you can cause them to move up to 2 meters in a direction that you choose. If you spend an action, you can move them up to 10 meters. Any difficult terrain that is no longer in the fissures returns to normal.
You can increase the damage by 1d8 for every two additional mana expended.
You can expend 1 additional mana so the duration changes to 1 hour/mana.