As an action, you can decrease the amount of light emitted from objects in a 1.5-meters radius sphere within 9 meters. You can decrease the light level by one step (from bright light to dim light, dim light to no light).
The change in illumination can be gradual (taking as long as 1 minute) or sudden (occurring immediately when you cast this spell). You can alter the level of illumination from its original level at any time during the spell’s duration.
You can gloom up to three areas at a time.
When you cast this spell, or as an action on a later turn, you can cause a gloomed area to engulf a creature. One creature of you choice within 9 meters of it must make a Fortitude saving throw.
On a failed save, the creature takes 1d4 necrotic damage and has disadvantage on the next attack roll it makes before the end of its next turn.
On a successful save, the creature takes half as much damage and doesn’t suffer disadvantage.
After the gloom engulfs the spell ends.
This spell’s damage increases by 1d4 when you reach 5th level (2d4), 9th level (3d4), 13th level (4d4), and 17th level (5d4).