Troll Repellent

This spell creates a thin, greasy, greenish mist that carries a potent odor in a 20 foot radius centered on the spell's target location. While this odor is unpleasant to most creatures, it is horrible to trolls, and if they fail a Constitution saving throw at disadvantage, they leave the area of the mist for the duration of the spell, refusing to enter again until it is gone.

The mist, unfortunately, is easily dispersed, making it useless in even a light breeze. The spellcaster must concentrate during the duration of the spell, or the mist instantly disperses.

At Higher Levels: Cast as a 4th level or higher spell, the repellent range is increased to 20 feet.