Transmute Rock To Mud

Transmute Rock to Mud (Wizard Attack 3)
Encounter * Arcane, Transmutation, Zone
Standard Action Area burst 1 within 10
Effect: The targeted area becomes difficult terrain until the end of your next turn. Any creature that starts its turn in the zone is slowed until the end of its turn. Any creature that is in the zone when the effect ends is restrained until the end of your next turn.
HP Threshold (10): A creature that is in the zone when the effect ends is instead restrained until the end of the encounter.