caustic fog

you cause a cloud of corrosive fog to appear. you can build the cloud out of 20 10-foot cubes. each of the cubes must be entirely within range. each turn, as a bonus action, you can move 2 cubes around.The cloud's area is heavily obscured. all the cubes must be linked with all the other cubes. A creature that enters the area for the first time on its turn or that ends its turn there takes 4d6 acid damage and must succeed on a constitution saving throw against you spell save DC or take 3d4 poison damage, have the poisoned condition , and be unconscious.a creature can make this saving throw at the start of their turns, ending the unconscious condition on that creature on a success.those conditions end on a creature after it has been fully outside the fog cloud for 1 minute.a creature can hold their breath to take half the acid damage only.Any objects in the cloud take only half the acid damage.

AT HIGHER LEVELS: for each spell slot level above 6, the cloud is made up of 5 more cubes, and you can move around 2 extra cubes. The base acid damage increases by 1d6 and the poison damage increases by 1d4.the time it takes for a creature to be fully outside the fog cloud to end the poisoned and unconscious conditions on itself increases by 1 minute.