Singetail

The Singetail is a medium-sized Stoker Class dragon that first appeared in Dragons: Race to the Edge.

Official Description
"Fiercely territorial, Singetails don't just breathe fire—they send it blasting out of their jaws, gills and tails. First discovered by Spitelout when he colonized Storehouse Island, the elusive Singetails prefer to scare away their enemies with long-range attacks, like hurling fireballs from their tails. However, Singetails also pose a danger in close-quarters combat by shunting jets of flame from their gills lining their exposed underbellies. No dragon or rider can ever get the drop on a Singetail due to its articulated eyes—they swivel to the sides and back of its head and give the Singetail a 360-degree lay of the land. Since it can look at two directions at once, the Singetail can act as its own tailgunner"

- Dragonpedia

"It's best not to get in a Singetail's way. These territorial Dragons can blast fire out of their jaws, gills, and tails! Sneaking up on a Singetail is hard enough, but finding its weak spot during battle is nearly impossible!"

- Dragons: Rise of Berk

Egg
In School of Dragons, Singetail eggs are oval-shaped and orange with red spots. They have a pock-marked texture, mimicking flowing lava. In Dragons: Rise of Berk the egg look more like a flaming bush, with frill-like fins lining across its length and a color scheme of red, orange and yellow. Singetail eggs also appear in the episode, "Family Matters". Here they are ovoid, have a scale-like pattern, and come in colors that reflect the colors of a standard Singetail - lime green, yellow, orange, and red.

Hatchling to Adult
Singetails have a wide, flat body and a long tail. They have four wings, like a Thunderdrum, but with the bigger pair being set lower on its back. They have a spiky face with chameleon-like eyes that allow it to see in multiple directions, as well as several big, sharp spikes along their backs and tails.

It has eight extremities (four wings and four legs), two more than any other dragon and with the rearmost pair seemingly a modified pair of extra hind limbs (unlike the Stormcutter, which has all four forelimbs as wings.

Titan Wing
Titan Wings are a pinkish color with dark purple stripes on their wings and back. They also developed another row of spikes along their back.

Endurance and Stamina
Singetails are able to evade other dragons and fly for long distances without tiring.

Speed and Agility
Singetails are very fast and agile, able to dodge attacks from its foes.

Eye Movement
The Singetails' articulated eyes allow them to see two different directions at once. Their eyes also swivel to the back and sides of their heads, giving them a 360-degree view that resemble a chameleon's.

Social Nature
Singetails will call others of their kind by spreading fire all over their current locations.

Firepower
Singetails can shoot fire from not only their mouths but from their tails and bellies as well. The fire that the Singetails produce are scarlet in color and can be used to mark their territories or as a signal to call for reinforcements from its own species. Singetails can also use the fire from their bellies to temporarily boost their speed like a rocket.

Strength and Combat
Singetails are fearsome adversaries in battle, for they are more than capable in taking on a Night Fury with little struggle.

Altitude
Spitelout Jorgenson discovered that Singetails do not like high altitudes. This serves as a route of escape if being pursued by one. The reason for this is undisclosed.

Fog
Singetails are shown to be very reluctant to fly into a heavy fog in "The Wings of War, Part 1". This is presumably because they cannot see where they are going, even though other dragons seem to be able to sense their direction. However, Krogan's Singetail had no problem flying through the fog.

Neck
When their necks are pinched in a certain spot, Singetails fall unconscious/asleep. This was shown in "Living on the Edge" when Krogan subdues an Ambered Singetail.

Skrill
In "Triple Cross", Viggo uses a Skrill to counter the Dragon Flyers' Singetails, knowing that the Skrill is the Singetails’ natural predator.

Season 3
The Singetail was first discovered by Spitelout Jorgenson on Storehouse Island in "Turn and Burn". When Stoick, Hiccup and Snotlout go to Storehouse island in search of Spitelout, Hiccup and Snotlout trigger a trap and get stuck in a net. When they ponder why Spitelout set up a dragon trap, they encounter a Singetail circling them. Spitelout arrives with Kingstail to rescue the group and leads the large beast away. Upon learning that Spitelout was making a storage house there, Stoick argues the beast itself makes the island too dangerous of a place to have the storage house. Hiccup tries to calm both sides down to reach a mutual decision, but it proves difficult with the Singetail's presence and the Jorgensens' point of views.

After determining the belly to be the weakness, they argue over who gets to take the shot before taking off. Spitelout shows them some places the Singetail has burned, and Hiccup knows something's wrong as the fires aren't concentrated. When they try to enact Hiccup's plan, they find out that the dragon's underbelly also emits fire. They soon figure out that the fire the first Singetail was making was calling for back-up. More Singetails arrive, and the team agrees to leave.

Season 5
Many Singetails are captured and enslaved to become steeds for the Dragon Flyers, with their leader Krogan riding an unusually large individual.

Season 6
The behaviors of the Singetails are explored even further, including the fact that they are the natural prey of the Skrill. In the season finale, all Singetails that have been captured and enslaved by the Dragon Flyers are freed when the Berserker Bewilderbeast let out a distress signal to protect its nest.

Dragons: Rise of Berk
The Singetail later appeared in this game too. Scorch, from Race to the Edge, and Winterwick were later introduced in the game.

School of Dragons
The Singetail appeared in the School of Dragons "Return to Dragon Island" expansion.

Trivia

 * The Singetail is the third dragon to have two sets of fully functional wings, with the first being the Thunderdrum, and the second being the Stormcutter.
 * While the Stormcutter has four front limbs modified into wings, forming an X-shape, the Singetail has one pair of wings on its shoulders and one pair on its hips, creating two separate pairs that work independently.
 * The Singetail's physical apperance greatly resembles a chameleon, a thorny lizard and a horned lizard combined.
 * The Singetail is the first dragon species with a secondary pair of wings that is larger than the primary one.
 * The Singetail has a pair of fins on each side of its tail, similar to the Night Fury.
 * The Singetail is the first dragon that can shoot fire from other parts of its body beside its head.
 * The tail of the Singetail resemble that of a Sand Wraith.
 * Deathlout's scars are purple instead of red, which seems to indicate that Singetails have purple blood.
 * In "Family Matters", Fishlegs discovers that Singetails despise Sagefruit.
 * The Singetail is one of the most feared dragons in the world.