Horerczy is a demon of Germanic mythology. While not much is known of this creature, it is known for its connection with the Alps, vampiric beings that hide in the mouth of the Horerczy.
When demon exhales, it vomits the Alps, in the form of butterflies, which venture out into the human world and are said to suck the breath from people's lips and even drink the blood from their nipples. They can also take the form of emaciated upright pigs, or sick dogs.
The Horerczy's exact appearance is unknown, however, it is known for its disturbingly wide mouth for when it vomits the butterflies. Other than that, its true form has not been witnessed. Although, it is documented that it can possess humans whom have trouble sleeping to the point of insomnia, but it can only accomplish that when one of the butterflies suck the breath from the victim's lips.
The demon can be exorcised much like any other demon, and it can also be deflected with the use of holy water. Additionally, spraying holy water in the bedroom of the Horerczy's next victim will prevent the butterflies from reaching them.