Insect Plague A5E

A roiling cloud of insects appears, biting and stinging any creatures it touches. The cloud lightly obscures its area, spreads around corners, and is considered difficult terrain. When the cloud appears and a creature is in it, when a creature enters the cloud for the first time on a turn, or when a creature ends its turn within the cloud it makes a Constitution saving throw, taking 4d10 piercing damage on a failed save, or half as much on a successful one.

The damage increases by 1d10 for each slot level above 5th.