The domain of your Faerie gang is under threat! Not so much directly but by a sudden invasion of Tourette’s Gremlins who are infecting the local humans.
If the Tourette’s Gremlins continue to spread and infect the humans they’re going to get wise that something strange is going on and may work out that faeries exist!
This cannot be allowed to happen.
In order to prevent it happening the local faerie lord (or some other boss) turns to your gang of selfish misfits for assistance. You are to track down the evil Tourette’s Gremlins and tear them from their homes, driving them out of the area or killing them as necessary.
Tourette’s Gremlins are like normal Gremlins, but smaller, denser and tougher. They are disgusting little creatures that infest a person’s body, replacing their tongue and making them swear, shout nonsense and twitch, all to the Gremlin’s great satisfaction and the production of their magic.
In this way they are much like the ‘tongue eating louse’, which, disgustingly, infests fish and replaces their tongue. To defeat them the faeries will have to find which people are genuinely infested and which are just foul mouthed and gaffe prone. Hopefully before they tear out too many human tongues…