Acidic Pit

You open a pit filled with acid at a point within range. Each creature within 10 feet of the point must make a Dexterity saving throw. On a failure, it falls 5 feet into a pit of acid below, taking 6d4 + 6 acid damage. On a success, a creature takes half as much damage from the flooding acid and can use its reaction to move up to its movement speed to the closest point outside of the area. If it cannot take a reaction or reach a safe space, it automatically fails its saving throw.
When a creature ends its turn in the pit, it takes 2d4 acid damage. The acid in the pit remains potent for 1 minute, after which it turns to vile sludge that deals no further damage. The pit remains filled with sludge until filled or cleared. It is considered difficult terrain.