Stone Dragons have a tough outer covering made of a stone-like material. They eat rocks, using the minerals they contain for nourishment and to keep up their stone outer shell. They rarely move, and are the heaviest of all types of dragons. Although they have wings, indicating flight ability, no one has ever seen a stone dragon flying.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

Hiccup dragoon and his family have had a problem since his birth: Hiccup has hiccups and can be heard for a very long distance. How long is determined by each dragon but on average it's roughly a mile. He has been ridiculed since birth by everyone, including his parents and hes also more hard-headed because when he was lighter he hit his head constantly. This has turned hiccup into a dragon battering ram and, within his own cave, is the strongest and heaviest of all the rock dragons. Unfortunately, this is the only positive aspect of the hiccups.