Black Tentacles

Duration: 1 minute, Concentration
Inky tentacles fill a 20-foot square on ground that
you can see turning it into difficult terrain.When
a creature enters the area for the first time or
starts its turn there, it makes a Dex save or takes
3d6 bludgeoning damage and is restrained. A
creature that starts its turn in the area and is
already restrained by the tentacles takes 3d6
bludgeoning damage. A restrained creature can
use its action to free itself, making a Str or Dex
check agai