Dream demons.
If they kill you in your nightmares, you die in real life. Thankfully, they only have one chance to get you before they can never enter your dreams again.
These days, they’re mostly a joke. Ponies figured out all the rules surrounding them ages ago. Young fillies even throw ‘nightmare night’ parties to mass inoculate themselves in relative safety.
And yet…
Every once in a long while…
More stories set in this AU can be found here.