Submaripper

"A powerful Tidal Class dragon, the Submaripper. I've read about them in the Book of Dragons. Much scarier in person."

- Hiccup

The Submaripper is a Tidal and Tracker Class dragon that first appeared in Dragons: Rise of Berk, although it was created for the fourth season of Race to the Edge.

Official Description
"Charybdis. The Kraken. Sea serpents. For centuries, frightened sailors have told tales of a beast that could turn the very oceans against them - if only they knew how right those myths were! The Submaripper dragon whips up whirlpools by creating a vortex in its mouth and start tsunamis when its massive body breaches the water's surface like a whale. Yet the Submaripper only unleashes these defenses when attacked by foolish Vikings and when it encounters its natural enemy, the Shellfire! The Submaripper is a gigantic deep-sea dragon that creates whirlpools and tidal waves to bring prey down to its waiting jaws. The Submaripper can be recognized by distinctive, foul-smelling bubbles that appear when it draws near. It reacts to vibrations in the water above it, and will follow them in the hopes of encountering food. It is typically not an aggressive dragon, but will lash out if threatened. The Submaripper doesn't breathe fire, but it vomits the shipwrecks it has ingested, spraying opponents with harpoon-studded debris. It also hunts prey by sensing their vibrations in the water, making the Submaripper the only dragon in both the Tidal and Tracker Classes!"

- Dragonpedia

"Hailing from the Tidal Class, the Submaripper has sent many a Viking to a watery grave with its ability to create inescapable whirlpools. Just watch out for its gas bubbles! This dragon is bulky, brawny, and brutal. It can decimate opponents by drawing them near and attacking with one of its mighty limbs or its Viking-size teeth."

- Dragons: Rise of Berk

Physical Appearance
The Submaripper is a large dragon, that can be best described as being similar in appearance to an eel with legs (as well as a few traits similar to frogs). The Submaripper has various wattles and kelp-like structures that line its back and hang off its legs and sides.

Egg
The Submaripper egg appears to have a dense, solid core, which is surrounded by a transparent layer of liquid, which is coated by another membrane. Suspended in the substance appears to be several gas bubbles.

Hatchling to Adult
This dragon is massive, said to have teeth the size of Vikings. In addition, it has an unusually large head-to-body ratio for a dragon, and a rounded head and snout. It has several lobs and nubs on its back, along with stripes along its body. The Submaripper has short necks and wings. It also has frog-like legs with webbed feet.

Titan Wing
This dragon, at its Titan Wing stage, is dark green in color. Its snout and stripes are yellow, and its back is a darker shade of red. Its heart shaped spines are bigger, and it has grown some on its feet as well (according to Rise of Berk).

Whirlpool Vortexes
The Submaripper has the ability to create a whirlpool by sucking the nearby water into its mouth. It is powerful enough to suck down large ships or dragons that are around the size of Scauldrons and powerful enough to pull dragons that are above the water.

Tidal Waves
Though this ability has yet to be seen, the Submaripper has been stated to be able to create massive tidal waves in order to drown its victims by slamming its massive body onto the water's surface.

Gas Bubbles
The Submaripper can breathe gas bubbles that produce a foul odor to alert its presence.

Firepower
The Submaripper vomits the shipwrecks it has ingested as harpoon-studded debris. This ability has yet to be seen.

Strength and Combat
The Submaripper has proven to be an extremely strong dragon, as it able to take on a Shellfire by using a full body tackle on the larger dragon. Underwater, the Submaripper can carry the weight of a large ship in its mouth, and could hold the weight of the cauldron with Hiccup inside, all while carrying Toothless on its tail to reach the surface.

Hunter
The Submaripper has proven to be quite an effective hunter, as it was able to devour ships, people, and dragons by using its powerful whirlpool vortexes.

Endurance and Stamina
The Submaripper is shown to be able to take multiple of Toothless' plasma blasts without showing any sign of being stunned or damaged from the hit.

Agility and Speed
It was shown to be able to move much quicker than the Shellfire, and is able to make fast turns underwater.

Aquatic
They are able to hold their breath for long periods of time under water.

Intelligence
When the Submaripper realized that Hiccup was the one who freed it and that he was drowning inside the diving bell, it returned the favor by bringing him and Toothless to the surface and placed them on their ship.

Season 4
Tired of the Dragon Riders' attacks on his operations, Viggo Grimborn traps a Submaripper in the Straits of Baldur in order to prevent trade ships from reaching Berk. It successfully demolishes several ships, with only Johann, who had previously encountered another Submaripper, surviving. Upon discovering the creature, the Dragon Riders attempt to free it but are initially unsuccessful due to their inability to stay submerged long enough to break the chains holding it in place. Fortunately, Hiccup is able to create a device that allows him to reach the Submaripper's depth with an air supply and uses Changewing acid to dissolve the chains. The Submaripper, now free, gets Hiccup back to the surface after he becomes trapped on the ocean floor.

Viggo later locates the Submaripper or another of the same species near Dragon's Edge and disturbs it. The dragon then attacks the Shellfire, which Viggo reveals is the natural enemy of the Submaripper, which he had kept in place as a contingency plan. The Submaripper's attacks allow the Dragon Riders to free the Shellfire, with both dragons subsequently fleeing the scene of battle.

Dragons: Rise of Berk
It first appeared in this game along with its Titan Wing form and the individual Shipsbane.

Trivia

 * The Submaripper's natural enemy is the Shellfire.
 * Given its resemblance to a frog, the Submaripper's jelly-like egg in the games may be based off frogspawn.
 * In Rise of Berk, the Submaripper was first distributed as part of a special event with the Scauldron. This is a reference to the fact that the Straits of Baldur, where the Submaripper is found during the events of Dire Straits, is known to be full of Scauldrons, with one even appearing in the episode.
 * The Submaripper is the only dragon that is part of two classes, in its case, the Tidal and Tracker Classes. This is due to its abilities being similar to both classes of dragons.
 * The Submaripper's intelligence was greatly underestimated by Viggo: while he set it up to either cut off Berk's supplies or kill Hiccup when he tries to free it, it turns out to be smart enough to recognize Hiccup and return the favor in gratitude, putting a dent in Viggo's plot.
 * The kelp-like growths on its body are similar to those found on some deep-sea fish used for camouflage.