Shellfire

The Shellfire appeared in season 4 of 2017 TV series called Dragons: Race to the Edge. The Shellfire is a gigantic Tidal Class dragon that first appeared in Dragons: Race to the Edge.

An enormous deep sea dweller with crustacean attributes, the Shellfire glides through the ocean at incredible speeds and tows the Dragon Hunter battleship bolted to its back. Reminiscent of a much larger — much angrier — horseshoe crab, the Shellfire shrugs off attacks with its durable carapace and delivers devastation with its protruding prong horns. In the past, unwitting sailors used to mistake its sizable shell for a landmass and scuttle their ships on it. That was the last time anyone ever heard from those sailors, but rumors of their demise likely gave Viggo Grimborn the idea to fasten a metal, dragon hunting warship to the Shellfire's back. The Shellfire is a gigantic Titan Wing deep-sea dragon with a flat hard back shell for protection. The Shellfire can launch huge flaming boulders that explode like giant cannonballs. Not much is known about it; Vikings of the distant past would mistake the massive shell for landmasses and wreck their ships on it.

As a Titan Wing, the Shellfire is one of the largest dragons to appear in the series. It has two long and slightly curved horns on the sides of its head, relatively long wings, and a rough dorsal protective shell. Overall The Shellfire dragon roughly resembles a trilobite and a horseshoe crab combined, with overlapping segmented scales covering its body forming a carapace-like armor. The dragon has four stubby legs and a pair of unique fan-shaped wings used mainly for swimming.

As massive Tidal Class dragons, Shellfires prefer the depths of the oceans to abide and hunt, and like Seashockers and Scauldrons, they rarely rise to the surface. When they do surface however, their massive armored backs are often mistaken for landmasses and used by seafaring Vikings to dock their ships on their travels, only for the disturbed Shellfires to dive beneath the waves sinking what's on their backs with them, never to be seen again.

Shellfires are quite shy and timid by nature, preferring to avoid most battles thus relying mostly on their massive sizes, armored carapaces and the unheard of depths they call home to fend off most attacks, even from Humans and their natural enemies, the Submarippers. However, if moved to battle, they have massive cranial and nasal horn-like projections combined with their massive raw strength, powerful limbs and plasma-imbued explosive rocks they can fire like mortars to put up quite the fight.

It is unknown if Shellfires can fly, as so far no individuals have been observed airborne, though judging by their sheer size and weight, comparatively small wings, and poor aerodynamic build, it is highly unlikely. Also, although undetermined, Shellfires most likely can stray on dry land, as their large and stumpy legs appear to be strong enough to support their massive weight.

Powers and Abilities

 * Firepower: Shellfires are capable of shooting a series of large plasma-charged boulders in a high trajectory that has a range of over a mile. These projectiles can be fired in rapid succession like a mortar and hit like bombshells. The projectiles whistle as they fly by before exploding once they hit their target. Their firepower most likely functions underwater as well, seeing as they are plasma charges, similar to that of the Night Fury, whose plasma blasts also function under water.
 * Strength & Combat: Shellfires have proven to be strong enough to carry the weight of an entire ship made entire dragon-proof metal tightly strapped on it's back, as well as a large crew of Dragon Hunters with little to no effort. Whilst in combat Shellfires use their massive body, combined with their weight and raw strength to slam against opponents, utilizing their carapace like armor and ridged spines as a defense. Although not shown on screen, Shellfires most likely use their nasal and cranial horns to ram and spar against opponents. Shellfires have shown proficiency in combat against both Viking and dragon alike, as shown when it repeatedly used hit-and-run tactics against the Dragon Riders to avoid being seen, as instructed by the Dragon Hunters on its back to do so. Viggo's Shellfire effortlessly defended itself against the Submaripper's blows, mostly utilizing its upper hand in size and armor to prevent any damage, and consequently speed and deep-diving abilities to retreat once irritated.
 * Endurance & Stamina: The Shellfire's armored carapace is so durable and resistant that it enables it to endure almost anything, even numerous blows from its natural enemy the Submaripper, showing no signs of injury, only slight irritation. Shellfires are also able to effortlessly travel long distances, as seen when Viggo's Shellfire traveled from island shore to island shore showing no sign of fatigue when it was under the control of Ryker Grimborn and the Dragon Hunters.
 * Speed: Shellfires is a very fast swimmer, as seen in the episode, "Shell Shocked, Part 2", when Viggo's Shellfire was able to dive and accelerate so quickly that it repeatedly avoided being seen by pursuing Dragon Riders, and, on one occasion, disappeared into the depths of the ocean so quickly a diving Hiccup Haddock and Toothless barely managed to catch a glimpse of the dragon before it vanished. Although fast, the Shellfire was shown struggling against the smaller but more agile Submaripper, mainly due to the Shellfire's size and overlapping carapace scales leaving little room for sudden movements.
 * Aquatic: As Tidal Class dragons, Shellfires can stay submerged underwater for extremely long periods of time and are perfectly capable of hunting just about anything at extreme depths.
 * Expelling Red Algae: When threatened, Shellfires will expel red algae from their gills that temporarily blinds and sickens their attackers.

Weaknesses
The Shellfire's massive size, durable carapace-like armor, and deep-dwelling capabilities enable it to endure mostly anything, though due to their timid whale-like nature they tend to escape fights and avoid struggles, rendering them relatively easy to capture and exploit, such as when one individual was captured and exploited by Viggo Grimborn and Ryker Grimborn in their conflict with Hiccup and the Dragon Riders.

The Shellfire's tendency to escape confrontations also enables Submarippers, their natural enemies, to often win skirmishes between the two species.