Blackhorrors are in the Mystery Class of Dragons. Their appearance is similar to a blend between a Night Fury and a Skrill. They have a deep midnight blue and indigo coloration. Their main color is midnight blue, but they also have indigo spots and an indigo belly. They have 2 hind legs, but no forelegs, being replaced with 2 fingered front wings. They have small spines on their backs like a Night Fury, they have a Night Fury's tail flaps, they have short necks, and their heads are similar to a Skrill's head, having several spines and a horn on the top of it's nose. Like Night Furies, they can retract their teeth. They have similar flying maneuvers as a Night Fury, but they fly much faster.
Blackhorror coloration allows it to blend into the shadows just like a Night Fury, but they keep their brighter bellies hidden at all times during camouflage. While they have their own roar, which is just as intimidating as a Night Fury's, often known to scare even a Night Fury, they prefer to be silent while hunting. Their hides are very thick and able to withstand any kind of sharp weaponry. They can rattle their spines to scare off opponents, and the spines can regenerate when broken off. Their teeth can retract like a Night Fury's teeth, and they are also known for their quiet flight. Their wings are so gently built, even a flap sound softer. Their signature ability is their electric/fire blasts that are just as strong as a Night Fury's plasma blasts.