Defensive Black Tentacles

Tentacles fill a 15-foot square on ground around you. For the duration, these tentacles turn the ground in the area into difficult terrain. The casters speed while concentrating on this spells is half of normal, but the tentacles move with them.

• Allies in the affected area are pushed back to the edge of the spells area.
• When a creature no more than one size larger than the caster enters the affected area for the first time on a turn or starts its turn there, the creature must succeed on a Strength saving throw or take 2d6 bludgeoning damage, be knocked prone, and then pushed back to the edge of the spells area. On success, they will take half damage and able to stand in the tentacles.
• A creature no more than one size larger than the caster starts its turn in the area must succeed on a Strength saving throw or take 2d6 bludgeoning damage, be knocked prone, and then pushed back to the edge of the spells area. On success, they will take half damage and able to stand in the tentacles.

The caster has advantage on any concentration checks made caused by attackers in the tentacled area.

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