5th-level Illusion

Casting Time: 1 action
Range: 120 feet
Components: S, M (a piece of whalebone)
Duration: Concentration, up to 1 minute
Class: Bard, Bender (air, water), Cleric, Warlock, Wizard
Sourcebook: Ryoko's Guide to the Yokai Realms

You create a 60-foot cube of swirling, green fog centred on a point within range that lasts for the duration. The fog heavily obscures the area, spreads around corners, is unaffected by wind, and thrums with illusions.
A creature that starts its turn in the area or enters the area for the first time on its turn must make an Intelligence saving throw. On a failure, the creature takes 5d8 psychic damage and becomes frightened of the illusions, which surround it. On a success, a creature takes half as much damage and isn’t frightened by the illusions. A creature that makes an attack against these illusions (AC equals your spell save DC) and hits can repeat the saving throw, ending the frightened condition on itself on a success and automatically succeeding on saves against the spell for the duration. The frightening effect ends for an affected creature if it leaves the area.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d8, and the area of the fog increases by 20 feet, for each slot level above 5th.