You choose an area of stone or mud that you can see that fits within a 40-foot cube and that is within range, and choose one of the following effects.

Transmute Rock to Mud.
Nonmagical rock of any sort in the area becomes an equal volume of thick and flowing mud that remains for the spell’s duration.
If you cast the spell on an area of ground, it becomes muddy enough that creatures can sink into it. Each foot that a creature moves through the mud costs 4 feet of movement, and any creature on the ground when you cast the spell must make a Strength saving throw. A creature must also make this save the first time it enters the area on a turn or ends its turn there. On a failed save, a creature sinks into the mud and is restrained, though it can use an action to end the restrained condition on itself by pulling itself free of the mud.
If you cast the spell on a ceiling, the mud falls. Any creature under the mud when it falls must make a Dexterity saving throw. A creature takes 4d8 bludgeoning damage on a failed save, or half as much damage on a successful one.
Transmute Mud to Rock.
Nonmagical mud or quicksand in the area no more than 10 feet deep transforms into soft stone for the spell’s duration. Any creature in the mud when it transforms must make a Dexterity saving throw. On a failed save, a creature becomes restrained by the rock. The restrained creature can use an action to try to break free by succeeding on a Strength check (DC 20) or by dealing 25 damage to the rock around it. On a successful save, a creature is shunted safely to the surface to an unoccupied space.