Book of Dragons

Fireworm

Class type: Stroker

Appearance: Common Fireworms are only about a few inches in length. They have hexagonal orangish-brown scales that glow a bright golden orange color when lit up. They also have five pairs of legs for a total of ten legs and white eyes that glow in the dark. They strongly resemble lizards, with their wide heads and long bodies. When they ignite, they glow orange, and sometimes even light their bodies on fire.

In How to Train Your Dragon: Hidden World, Fireworms appear somewhat larger in size than in the TV series. They have short spines down their backs and some under their throats. They have clearly visible pupils, and their nasal horn is colored darker than their skin. These Fireworms also only have four pairs of legs in contrast to the five pairs that their series counterparts have.

Fireworm Queen/Princess

Fireworm Queens/Princesses look similar in appearance to the average Fireworm, but have some differences that make them stand out from the rest. For instance, while the common Fireworm can fit in the palm of a hand, the queen is many times bigger, her size is comparable to that of a Boneknapper. She also possesses several horns located at the back of her nape and the front of her snout that together resemble a crown. When not heated-up or near her nest, the Fireworm Queen's normal skin color is a pale gold, with tan colored horns, spots, and underbelly. She also doesn't glow in this state. Fireworm Queens are, like the name suggests, always female and if another female Fireworm were to be born in a nest which already has a queen, the newly born Fireworm (the Fireworm Princess) would fly off to start a nest of her own. Fireworm Queens and Princesses would appear to be the only females in the species.

Titan Wing Fireworms are very colorful. They have a neon green body with distinctive scales. Their head, tail and half their wing bones have hints of cyan while the other half of the wing bone is yellow. The protuberances at the back of their head are yellow too. Their wings are blue in color. A row of thin spines run along their back, and they have five pairs of legs.

Abilities: 

All Fireworms can heat up their skin to a temperature expressed to be hotter than the sun, hot enough to be able to burn almost anything. While doing so they also generate a great amount of light, and sometimes, they even set themselves and surfaces they walk on aflame. It would appear that the closer two Fireworms are to one another, the brighter they will shine. This ability is used as means of self-defense and for lost individuals to find their way back to the nest. A great number of Fireworms using this ability are virtually unapproachable and undefeatable, only moving when exposed to their main weakness.

Some Fireworm individuals, such as Solar Flare, appear to have extremely hot skin. Due to this, they can only exit their caves during the warmest days of hot summers, and they remain in their nests during cooler days. This is probably because reptiles, like dragons, are cold blooded and their body temperature depends on their surroundings, meaning that being in the cold may cause the Fireworm to lose too

Fireworms are not shown to be able to breathe any fire, but Fireworm Queens have very powerful, bright, napalm-typed fire breaths that emit small firework-like particles (indicating extreme heat) Fireworm Queens also appear to have a hotter, less destructive, more concentrated and accurate version of their fire breath similar in appearance to a magnesium fire breath. It seems that they use this fire type while in their nests to avoid accidentally destroying anything and as a tool, to shape the cave systems near the nest to their liking.

 it appears that Fireworm Queens can combine their firepower with other Stoker Class Dragons (at least Monstrous Nightmares) to create a very powerful, force field-like blast of fire to defeat opponents. This ability appears to regenerate both participant's strength and health as one Fireworm Queen was severely wounded when Hookfang  picked her up to initiate the ability, and, after they finished performing their combined firepower, the Fireworm Queen was completely healed and back on her feet. This fire is much hotter than their ordinary fire, as it is able to cook the mucus off of a Cavern Crasher, which the Fireworm Queen was unable to do with her regular fire.