Squirming, ebony tentacles fill a 20-foot square on ground that you can see within range. For the
duration, these tentacles turn the ground in the area into
difficult terrain.
When a creature enters the affected area for the first time on a
turn or starts its turn there, the creature must succeed on a
Dexterity saving throw or take 3d6
bludgeoning damage and be
restrained by the tentacles until the spell ends. A creature that starts its turn in the area and is already restrained by the tentacles takes 3d6 bludgeoning damage.
A creature restrained by the tentacles can use its action to make a
Strength or
Dexterity check (its choice) against your spell save DC. On a success, it frees itself.