Casting time: 1 Action
Range: 90 feet
Components: V, S, M (a piece of tentacle from a giant octopus or a giant squid)
Duration: Concentration, up to 1 minute
Squirming, ebony tentacles shall fill a 20-foot square on the ground which you’re able to see within a range. For a specific duration, all of these tentacles shall be turn the ground in an area into a difficult terrain. Of course whenever the creature shall be entered an affected area for the first time on a particular turn or else starts its turn there, the creature should be succeeded on a Dexterity saving throw or else take 3d6 bludgeoning damage and it must be restrained by the tentacles unless until the end of this spell.
Also read contingency 5e spell
Al though a creature which starts its turn in an area and it is already restrained by the tentacles takes 3d6 bludgeoning damage. A creature shall be restrained by the tentacles could use its action for making a Strength or else or Dexterity check (its choice) against your spell save DC. On a success, it frees itself.