Black Tentacles

4th-Level Conjuration
Casting Time: 1 action
Range: 90 feet
Components: VSM (a piece of tentacle from a giant octopus or giant squid)
Duration: (C) 1 minute

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.

creature restrained by the tentacles can use its action to make a Strength (Athletics) check against your spell save DC. On a success, it frees itself.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the bludgeoning damage increases by 1d6 per spell level above 4th.

Source: PHB 238, SRD

Changelog

Added upcasting option.