Stinking Cloud

3rd-Level Conjuration
Casting Time: 1 action
Range: 120 feet
Components: VSM (a rotten egg or several skunk cabbage leaves)
Duration: (C) 1 minute

You create a 20-foot-radius sphere of yellow, nauseating gas centered on a point within range. The cloud spreads around corners, and its area is heavily obscured. The cloud lingers in the air for the duration.

Each creature that is completely within the cloud at the start of its turn must make a Constitution saving throw against poison. On a failed save, the creature spends its action that turn retching and reeling.

Nonmagical food, drink, and water in the spell’s area is befouled. If a creature consumes it, it gains no benefit unless it is immune to poison, and make the saving throw as if they were in the spell's cloud effect.

Creatures that don't need to breathe or are immune to poison automatically succeed on this saving throw.

A moderate wind (at least 10 miles per hour) disperses the cloud after 4 rounds. A strong wind (at least 20 miles per hour) disperses it after 1 round.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the radius of the cloud increases by 5 feet for each slot level above 3rd.

Source: PHB 278, SRD

Changelog

Added note that spell befouls nonmagical food and drink.
Added upcasting option.