The book of dragons

Gembreaker

Gembreakers greatly resemble beetles, possessing similar wing shells and having the same manners of flight. They also have a large rhino-like horn which appears to be made of crystal. They also have crystals on their elbows and their tails, shaped like a morning-star. They are likely descended from Gronkles and Rumblehorns primarily, as the insect-like structure that houses their wings can only be found on Rumblehorns. Gembreakers fire a highly flammable, exploding loogie blast, remarkably similar in shape to the lava blast of a Gronckle. When in contact with a dragon's wings it will temporarily set them on fire. Gembreakers are said to possess extreme tracking skills, likely due to their similarity and possible relationship to Rumblehorn dragons. They can use their sense of smell to track other dragons that have passed after some time, As shown by Plowhown if the dragon sits down and cover their body with its back it looks like a rock formation which can help her to hide from people or dragons. Its colors also helps it easily to blend with the crystal formations from the Hidden Realms if it just stays immobile.