Exuberant Fever

Curious, the King reached down and grasped a cherry from the edge of the plate. Examining it on all sides, he found nothing to be amiss. Smelling it, it's scent was no more or less sweet than he expected. Looking around, no one seemed to think the plate of food out of place.

"What's the harm? He thought, placing the cherry in his mouth. Before he could chew, Somerild appeared beside him, a stern look on her face, and gripped his mouth with one hand.

"What do you think you're eating, dear husband?" She chided, a hint of amusement in her voice.

"A cherry?" Came his muffled response.

"And what did I tell you about eating mysterious food in this forest?" She released him, and he took the hint, spitting the cherry onto the ground.

"Not to eat mysterious food, for the fear of it being a gift from faeries. I would hardly count a plate a food in the center of our camp mysterious..."

"Does a platter of silver, engraved in a style unfamiliar, not seem mysterious to you?"

He looked at the platter again, closer now, and saw what she spoke of. A fine silver platter, like he would have the servants use in the castle but out of place so far afield. Looking even close, he saw the engraving for what it depicted. Little figures, humanoid but for the wings that spread off their backs.

fairies.

— The Threemetal Cycle, a 4th era play

While fairies are, usually, simply well meaning pranksters, they're not usually super... aware of mortal life. What amuses them can be harmful to us in various ways. Such is the case with their food, which is one of their favorite pranks. They leave it out so that someone will find it, and given it's charms and qualities, consume some or all of it.

This induces a sort of overwhelming euphoric feeling in the consumer. If one does not care about what others see them doing, then it's not a problem. If one is prone to shame, however, they will likely hear about their actions for years to come. Dancing, partying, and other such activities become commonplace, and the euphoric temperament continues in direct correlation to the amount of fairy food an individual ate.

All the while, the body will be rejecting the food, not meant for human consumption as it is. Thus the "fever" implied by the name. Sweating, sallow features, giving the patient a sort of manic look if the illness continues on too long.

It is best if one can restrain the victim, and simply allow them to ride out the effects. Otherwise one must keep a watchful eye on them so that they don't do something that they'll come to regret, or possibly hurt themselves on accident.