Aura of Putrescence

Target yourself or another creature you can see within range.  The target emits a 20-foot-radius sphere of nauseatingly bad-smelling gas that can't be seen by normal vision without a Wisdom (Perception) check against your spell save DC.  The cloud spreads around corners. 

Each creature that is completely within the cloud at the start of its turn must make a Constitution saving throw (the target is affected).  On a failed save, the creature takes 1d6 poison damage and spends its action that turn retching and reeling.  On a successful save, the creature takes 1 poison damage for each die of poison damage it would've taken on a failed save.  Creatures that don't need to breathe or are immune to poison are immune to this spell.  Creatures that have advantage on Wisdom (Perception) checks relying on smell or taste have disadvantage on this saving throw. 

This spell has multiple versions, each of which must be learned and prepared separately.  You are immune to any version that you know (if you don't prepare spells) or have prepared (if you do). 

At Higher Levels.  When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 for each slot level above 4th.