Swarm of Flies

Cast (Action) (Concentration, Up to 1 Minute): You summon a cloud of biting, stinging insects in an 8-square cube centered on a point within 12 squares of you. When a creature moves into the cloud for the first time on a turn or starts its turn there, it takes poison damage equal to half the number of faces on your Fighting die.

The cloud spreads around corners and it blocks vision entirely. At the GM's discretion, a wind of moderate or greater speed disperses the insects, ending the spell early.

Once you have cast Swarm of Flies, you must finish a long rest before you can cast it again.

Not into the whole "bugs" aesthetic? Swarm of Flies can just as easily model a plume of volcanic gas (no changes), a whirlwind of glass knives (dealing mundane damage), an enervating mass of shadows (dealing necrotic damage), or a classic raging inferno (dealing fire damage and igniting flammable objects that aren't worn or carried). Reduce the size of the cube to 6 squares for damage types other than poison damage and mundane damage.