Elemental Trapper

Prerequisite: The ability to cast at least one spell.

Your spells that do elemental damage leave a lingering danger on the battlefield. When you gain this feat, choose one of the following damage types: acid, cold, fire, lightning, or thunder. When you cast a spell of 1st level or higher that does the chosen type of damage, you can choose to leave behind an elemental cloud that fills the same area as the original spell. Spells that target individuals create a 5-foot-diameter cloud in the target’s space. The cloud is stationary and lasts until the start of your next turn. Creatures that end their turn inside an elemental cloud take damage of the cloud’s type equal to your spellcasting ability modifier + the level of the spell slot expended when the spell was cast.