Changewing

"Changewing. Even newly hatched dragons can spray acid. Kill on sight."

- Hiccup reading from the Dragon Manual

The Changewing is a Mystery Class dragon most notable for its ability to change its color along with its surroundings.

Official Description
"The chameleon-like Changewings are skilled predators and some of the deadliest dragons in the Book of Dragons. Their camouflaging skills are second to none, allowing them to blend in with rocks, trees, foliage and even buildings. Additionally, Changewings often change colors based on their moods and surroundings. Instead of fire, they shoot hot, corrosive acid that burns through wood and rocks. They are also extremely agile and fast, even when moving along the ground. Changewings have a social structure similar to a lion pride. The female Changewings do most of the hunting and defense."

- Dragonpedia

"This Mystery Class elusive expert in camouflage can shoot hot corrosive acid that can burn through wood and rock (and Vikings!). The Changewing distracts opponents at a distance while lobbing balls of acid in their general direction."

- Dragons: Rise of Berk

Egg
In Dragons: Riders of Berk, Changewing eggs have a triangular shape, and they change colors while casting bright lights. They appear to have a solid core encased in another translucent shell. In Dragons: Rise of Berk and School of Dragons, Changewing eggs also have a translucent outer shell, but instead, wavy red stripes on it and emit a faint white glow.

Hatchling to Adult
Changewings are usually red or green. They have teeth protruding out their lip from their lower jaw and yellow eyes. They possess These horns are blue, together with a small pointy ledge on the top of its snout. A row of sharp, blue spines run down their neck to their tail. Their wings are red with blue edges. Their size is close to Monstrous Nightmare as shown by Hookfang trying to rescue Snotlout.

Titan Wing
In Rise of Berk, Titan Wing Changewings look relatively similar to that of a regular adult one. However, the edges of their wings become sharper and their color turns. They are dark green and their wings have a red edges and splotches of black. The blue spines turn red and the blue horns at the side of their head turn green.

Camouflage
The Changewing's most noticeable attribute is the ability to change the color and texture of its scales to match that of their surroundings. They usually blend in with their surroundings while approaching their prey, then transform back into their default colors. The only body part that Changewings can't change are their eyes, which they use to hypnotize victims before an attack. The Changewing's camouflage can also be rendered defunct if they are exposed to Hideous Zippleback gas.

Acid Blasts
Unlike most other dragons, the Changewing can launch concentrated streams of acid at victims. The acid is green in color and is extremely corrosive. This acid can burn through most, if not all, materials in seconds. However, in the Dragons: Riders of Berk episode "We Are Family, Part 2", Alvin introduced Hiccup to a caged Changewing which shot hot acid at a metal bar, but the bar did not burn. This was also demonstrated in Dragons: Race to the Edge episode "Night of the Hunters, Part 1" when Snotlout's helmet got hot Changewing acid on it but did not burn through. This means that the Changewings acid cannot corrode metal. However, it is shown in "Dire Straits" that Changewing acid can melt dragon-proof metals. The acid is also highly viscous, able to stay intact underwater. This may indicate an oil-based substance, as it is water-insoluble.

Hypnosis
Changewings have the uncanny ability to hypnotize their prey, when they do that, their eye pupils dilate into slits, then swirl around. Their ability is said to be so powerful it could hypnotize a Purple Death.

Strength and Combat
They have been shown to be very strong, capable of holding young people with their claws and tail with no struggle. These dragons don't seem to be in battle type as they proven to be to work as team against their enemies only as more then one.

Speed and Agility
Their agility and speed has shown to be quite good. They have been shown to have good reflexes allowing them to dodge attacks in battle. They are relativity fast, though they mainly rely on their camouflage.

Climber
Due to their long claws they are shown to be great climbers that can climb on any type of surface.

Prehensile tail
Changewings have flexible tail for gripping as they are able hold objects. They are able to lift up Vikings with their highly flexible tail with little to no effort.

Senses
Quite possibly, their scent of smell might be strong enough to find their stolen eggs from their island to Berk. Though more likely, they followed the Dragon Riders scent to track down their missing eggs from Snotlout.

Firepower
Even though Changewings have not yet shown the ability to produce fire in the Series, a specimen in the Book of Dragons (Short) was shown to do so. It is currently unknown if this was an animation error or not, but Hiccup's Dragon Map in the sequel also has a drawing of a Changwing with a note next to it stating that it can shoot blue fire. One individual, Incognito, from Rise of Berk is seen breathing yellow fire.

Behavior and Personality
Changewings nest in large, tall forests in packs. They group together for common goals, or in other words, they are team players and will stop at almost nothing to remain in possession of their eggs. Also, Changewings are very curious creatures, and as Hiccup describes, "whatever they see, they want to copy". Changewings are mostly nocturnal, so that they can hide more easily.

A Changewing's egg has gem-like qualities and is green in base, but its aura glows in multiple colors. Some Vikings will mistake these for 'Stones of Good Fortune'. Changewings are known to be very cooperative and work together to accomplish their goals. Multiple Changewings help one another acquire one of their eggs, and do not rest or leave until all of their eggs have been found. The way a Changewing pack works is very much like how a lion pride works. The females do most of the hunting and fighting, as well as defending their territory. Changewing packs sneak up on their prey--be it a swarm of smaller dragons or a downed dragon, then herd them together or circle a single victim, then pick them off one by one, much like how Black-tip Reef Sharks pick at a bait ball--a compact school of fish they round up against the surface of the water.

Changewings are very maternal dragons, and will protect their young at all costs. However, they have also been known to raise Vikings as baby Changewings. This has only been seen once, when a particularly maternal Changewing captured Snotlout and cuddled and played with him until Hiccup and Toothless got her to drop him. Like some reptiles such as the snake, Changewings periodically shed their skin, as seen in "A Gruff Separation". The shed seems to be very thick and come off in fairly uniform strips. How often this is done and why exactly is not discussed. The shed skin still retains its camouflage ability, such that it renders things nearly invisible rather than just changing colors to blend in. How the skin by itself determines the composition of its surroundings is also not discussed, nor if there is a finite limit to it, since the skin has been cast off. Use of this potent tool is only seen in "A Gruff Separation".

Weaknesses
The Changewings skin is vulnerable to attack, as it is softer due to its color-changing properties. In addition, they can't hide if nothing is in their area for them to camouflage against, such as the sky. When Changewings get threatened, injured, or scared, they can't control their color changes, making them easier to see.
 * Yet in "When Darkness Falls" and "Snuffnut", they are able to camouflage themselves against the sky. It's unclear if possibly they can camouflage against a dark sky, or maybe some sub-species has evolved to take on that trait, similar to the Speed Stingers evolving webbed feet in "The Next Big Sting".

Training
They enjoy mimicry, so if you mimic them, be it by their noises or their movements, they will find you fascinating.

In the Dragons: Race to the Edge, Season 3 episode "Enemy of My Enemy", Dagur the Deranged diverts a menacing Changewing by clasping his hands together at his mouth and making a deep, fast whistling sound, almost like some sort of bird call. The Changewing appears caught off guard or perhaps is intrigued, then turns away and looses interest.

How to Train Your Dragon
It made a cameo appearance in the film when Hiccup was looking through the Dragon Manual.

Book of Dragons
They are listed as one of the Mystery Class dragons, and it is confirmed that not only can Changewings spit acid but change colors and hypnotize as well. It is also shown that Changewings are very curious dragons. They are seen in a 2D animation where one burns Bork the Bold while he is making a campfire. The Mystery Class symbol resembles one.

Dragons: Riders of Berk
In the episode "Gem of a Different Color," the Changewings were found on a island. Fishlegs, on his own "secret" island, finds a strange glowing gem while with his beloved dragon, Meatlug. Taking it back to Berk, Gobber identifies it as a "Stone of Good Fortune, (as Gobber gets "Stones of Good Fortune" and Changewing dragon eggs mixed up) causing the citizens to swarm Fishlegs, offering him valuable trades. Overwhelmed, Fishlegs, after refusing to give it to Snotlout, asks Hiccup to help him return it, so that he can forget all about it.

The teens, excluding Snotlout, who is secretly trailing, take it to the island, where they find many of them in nests, and Hiccup realizes that they are truly dragon eggs. Fishlegs returns it, realizing that it must've fallen from its nest and that he had separated it from its mother. When they attempt to leave, the Changewings trail them, invisible, trying to attack them using their acid. They escape, but Snotlout enters undetected and steals many of the eggs. The next day, Snotlout auctions them off, and the gang tries to convince him something terrible will happen if the eggs remain here. He ignores them and declares a "No returns" policy. The Changewings gradually show up, getting their eggs back, but destroying the village in the process. Stoick and Gobber try to fend them off, but realize that it would be impossible to attack things they can't see.

Hiccup and the gang scramble to return the eggs, and they end up with giving them all back, but the Changewings don't leave. Fishlegs realizes Snotlout has kept one and confronts him, displaying anger and strength that scares Snotlout into giving it back. Fishlegs then nervously tries to find them, and the Changewings surround Fishlegs and reclaim their egg from him. Afterwards they roar and terrify the unfortunate Viking but leave him completely unharmed. Hiccup later claimed they would need to find one so they could train it, possibly inferring they will later appear again.

A Wild Changewing was found where it hid an entrance to Bork's cave in "We Are Family, Part 1" and "held Snotlout hostage" until Hiccup freed him. The Outcasts had one kept in a cage on their island which along with a caged Whispering Death and Scauldron was later used on an attack on Hiccup, Mildew, and Flystorm.

Dragons: Defenders of Berk
During their first 'Flight Club' drill in "Live and Let Fly," the riders went Changewing Island, in hopes of sharpening their skills against Changewings and learning more about them. While Hiccup and Fishlegs explained about their pack behavior, the twins spotted the pack of Changewings attacking Bjorn Boar. The twins accidentally alerted the dragons, and the Riders make a quick escape by heading to the clouds, where the Changewings could not escape. The Outcasts then used a herd of wild Changewings during a diversion, thankfully, the dragon riders chase them back to Changewing Island.

In "Free Scauldy," while searching for the Screaming Death, Hiccup, Fishlegs and the twins discovered a Scauldron that had been washed ashore on Changewing Island and been trapped by one wing under a pile of rocks. Despite the threat posed by the Changewings, their dragons refused to leave the Scauldron to die of dehydration, forcing Ruffnut to tame the dragon - which she named Scauldy - so that the others could remove the rocks and fashion a splint for the damaged wing.

Dragons: Race to the Edge, Season 1
In "When Darkness Falls" a pack of wild Changewings attack the Night Terrors without a leader, but they retreat when Smidvarg, the leader, came and make the formation of the big Night Terror.

Dragons: Race to the Edge, Season 2
In "Night of the Hunters, Part 1", the riders try to capture a wild Changewing to use its acid to unlock the Dragon Eye. Unfortunately, the Changewing is scared away by Tuffnut, much to the gang's disappointment, but he then reveals that he had set up a trap and the Changewing is captured the moment it took off. The Changewing quickly spits at Snotlout's helmet and fled, leaving the gang to collect the acid on the helmet.

Dragons: Race to the Edge, Season 3
In "Enemy of My Enemy", a wild Changewing attacks Dagur and Hiccup but Dagur makes a sort of dragon call and the Changewing leaves. Later, when the captain of the dragon hunters hides behind a rock, the same Changewing attacks him and presumably kills him.

In "Defenders of the Wing, Part 1", the riders free a captured Changewing from the hunters.

Dragons: Race to the Edge, Season 5
In the episode Snuffnut, Tuffnut fakes his death by appearing to be eaten by a Changewing. Devasted by this, Ruffnut makes that Changewing her "new brother", naming him Snuffnut and painting Tuffnut on his belly.

Dragons: Race to the Edge, Season 6
In the episode "A Gruff Separation", the twins take the Thorston Induction Trials. One of the tasks is collecting a shred piece of Changewing skin; both Tuffnut and Ruffnut manage to complete the task by paralyzing the dragons with Speed Stinger venom.

DreamWorks Dragons: Wild Skies
Described as 'Keen Sight, Master of Disguise', this dragon is available on Unlandable Cove. It remains camouflaged in a pile of rocks by the cove until you approach it to train it.

Dragons: Rise of Berk
Along with Melting Wing, Tuffwing, Edgewing and Incognito, the Changewing appeared in Rise of Berk.

School of Dragons
The Changewing also appears in School of Dragons.

Trivia

 * Strangely, according to Book of Dragons, the Changewing breathes acid instead of fire while the special shows one burning Bork the Bold. It could be that their fire is greatly reduced compared to other dragons.
 * As seen in many episodes, Changewing acid can melt trees but can't melt rocks or metal (excepting Viggo's dragon-proof chains). This would mean that the acid melts mostly living things.
 * Changewing acid is shown to be immiscible in water, suggesting that it may not be "acid" per se but a highly corrosive nonpolar solvent.
 * The Changewing's acid is likely to be the magic acidundefined(FSO3H·SbF5), as in the franchise it can melt almost everything, produces a horrible black smoke, and is green in color.
 * The Changewings facial appearance is similar to that of the Diplocaulus, an extinct, prehistoric amphibian from the Permian period.
 * The Changewing is one of the dragons that is mostly portrayed as an antagonist, with even Hiccup telling Trader Johann that Changewings (unlike other species) are known to attack unprovoked. However despite their wild and aggresive tendencies, they apparently can be tamed and trained.
 * The Changewing's ability to mimic its surrounding in the episode of "Gem of a Different Color" is different from what's shown in Book of Dragons. Its color mimicry in "Gem of a Different Color" is fixed on every part of its body while in Book of Dragons, Changewings mimic different colors for different parts of its body, even if it's not in contact with Changewings body making it truly invisible with a little distortion.
 * Changewings are similar to RainWings from the Wings of Fire book series. Both can change color to camouflage themselves, have "Wing" in their name, and spit acid that melt living things.
 * A Changewing's ability to hypnotize is most likely based on the books, where dragons have a hypnotic gaze.
 * While Changewings in the animated short, Book of Dragons, camouflage themselves in a chameleon-like way by changing color, in Dragons: Riders of Berk, they disappear completely. In Dragons: Wild Skies, they disappear almost completely; however, a faint outline of the dragon is still visible.
 * In Book of Dragons, it was said that Changewings display mimicking behavior and love to copy whatever they see. These dragons never show this behavior in the TV Series, most likely because they were defending their territories when the riders encountered them.
 * The Changewing is the first dragon species that can change its color, followed by the Hobblegrunt.
 * Changewings were the first dragons to almost make every Viking on Berk abandon their homes, before the Speed Stinger in "Frozen".
 * Changewings are actually more similar to an octopus than a chameleon due to the fact that chameleons change color to show mood rather than for camouflage. Octopuses change both their color and skin texture to camouflage themselves, much like a Changewing.
 * If this is the case, the Changewings ability to hypnotize may be based on the color-changing ability of a cuttlefish, which it uses to distract its prey.
 * The wings of a Changewing are shown to not be double-jointed similar to that of a Thunderdrum.
 * In a piece of concept art, a Changewing is seen inflating, which might be a scrapped ability of this dragon.
 * This ability was later reused for the Buffalord in Race to the Edge.
 * According to Hiccup's Map, Changewings are able to breath blue fire.
 * The Changewing share some similarities with the Demiguise, a magical creature from the Harry Potter franchise.
 * Both can camouflage.
 * Both of their pelts can make people or objects that they cover invisible.