Doom of the Pit

4th-level conjuration

Casting Time: 1 action
Range: 120 feet
Components: V, S, M (dust from a stone quarry)
Duration: 1 minute

You create a ripple of dark energy that destroys everything it touches. A 10-foot-radius, 10-foot-deep, cylindrical extradimensional hole appears on a horizontal surface of sufficient size. Since it extends into another dimension, the pit has no weight and does not otherwise displace the original underlying material. You can create the pit in the deck of a ship as easily as in a dungeon floor or the ground of a forest.

The pit’s radius expands by 10 feet at the start of your turn each round for the duration. Any creature standing in the original conjured space, or on a space taken up by the pit as it grows, must succeed on a Dexterity saving throw to avoid falling in. Any creature adjacent to the pit when it expands must likewise succeed on a Dexterity saving throw to avoid falling in. Creatures subjected to a successful pushing effect (such as by a spell like gust of wind) may not make this saving throw. Creatures that fall into the pit take falling damage as normal.

The walls of the pit are slick and slimy, requiring a DC 15 Strength (Athletics) check to climb. Creatures and objects that remain in the pit take 1d6 necrotic damage at the start of each of their turns. If you fall into your own pit, you take damage; then the spell ends and you are incapacitated for 2 rounds. When the spell ends, the floor of the pit rises, bringing creatures in the pit back up to the original surface. Each creature in the pit must then make a Constitution saving throw. On a failed save, the creature is stunned for 2 rounds after the spell ends.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you can increase the depth of the pit by 10 feet for each slot level above 3rd.