Circle of Doom

inside the range of the spell the sky is covered by black fog so thick no light can pierce it, the air is heavy, reducing 5 ft of movement for every creature and providing disadvantage on any strength checks or saving throws, any ranged weapons or thrown objects range is reduced by half. Any living creature except for the caster has their organs failing slowly, and every round they must make a constitution saving throw or take 2d8 necrotic damage.