Call of the deep

Colossal tentacles burst from the ground at six different points you can see within range. These tentacles take up a 20-foot-radius and 40-foot-height cylinder centred on each point you choose.

Any enemy creature within range when the tentacles appear or when they enter the range for the first time in a turn must make a dexterity saving throw and takes 8d8 acid damage and 8d8 bludgeoning damage on a failed save and is restrained, being caught within the tentacle. A restrained creature takes 4d8 bludgeoning damage and 4d8 acid at the start of each of its turns and can make a strength save to escape and end the effect on itself. A creature takes half damage and is not restrained on a successful save. A creature in the area of more than one tentacle is affected only once.