THE THREE-HORNED GOAT FLY
The three-horned goat fly is, due to it's size, a rather harmless creature. It is, however, commonly seen as an annoyance, and shouldn't be underestimated when it shows up in swarms.
Goat flies usually only prey on the crops of farmers, however in greater numbers, they may very well also attack larger creatures, although usually a swarm only grows that large during summer, when the goat fly populations increase due to the larger amount of available food.
The common three-horned goat fly basically is a fly, however it bears the head and legs of a goat. The eyes of the goat fly usually are a fly's, but there are rumours of some with normal eyes. Goat flies are found all across the world in different color variations, rarely also with more or less than three horns.
The goat fly is a magical creature and once was summoned by the famous wizard Goatbeard, who, according to himself, meant to summon an ordinary flying goat for travelling, when a fly flew into his summoning circle JUST as he finished the spell. The resulting creature fled, and is assumed to be still alive and breeding to this day, as goat flies don't die of old age.
Due to their magical nature, goat flies only require food to gather the mana required to multiply, it is highly advised that one either
1) Avoids using any magic at all against them, or
2) Uses spells that are destructive enough to kill the fly before it even has a chance to absorb the mana.
The Three-Horned Goat Fly(sp) is one of the many beasts I've had in my head for a while now. I'm not claiming originality here, there will be more uploads like this - Bestiary entries, People profiles and lore about the world. I'll see if I can squish it up into a folder later.