Alluvial Pool
8th-level conjuration (Druid,Sorcerer,Warlock,Wizard)
- Casting Time: 1 action
- Range: 90 feet
- Components: V, S, M (a vial of ooze)
- Duration: Concentration, up to 1 hour
Thick ooze fills an area of the ground you choose within range. The area by default is a 50-foot square, but its dimensions may be whatever you wish, provided it is one continuous pool and the total surface area does not exceed 2500 square feet. The resulting pool has a depth of 10 feet and is difficult terrain. The area looks like a shallow pool of water at first glance, and any creature that was not aware of the spell being cast must make an Intelligence (Investigation) or Wisdom (Perception) check against your spell DC to believe otherwise before contact is made with the pool.
A creature entering the pool for the first time on a turn or starting its turn there must make a Dexterity saving throw, taking 4d6 acid damage on a failed save and sinking into the pool, as the grappled condition. On a successful save, the creature takes half as much acid damage and is not grappled. A grappled creature can use its action to make a Strength (Athletics) or Dexterity (Acrobatics) check (its choice) against your spell save DC. On a success, it frees itself. A creature of size Large or smaller that fails the saving throw while already grappled by the pool is also restrained against your spell save DC.
A restrained creature can't breathe, and any non-magical metal objects it carries begin to corrode. When the restrained creature takes acid damage from the pool, non-magical metal weapons and armor take a permanent, cumulative -1 penalty to their damage rolls and AC, respectively. If this penalty on a weapon reaches -5, the weapon is destroyed; similarly, armor is destroyed if its AC is reduced to 10. Other metal objects take cumulative damage as well, as the pool eats through a 1-inch-thickness of non-magical metal each round it is immersed.