Hideous Zippleback

"A Zippleback? Exotic. Two heads, twice the status."

- Hiccup

The Hideous Zippleback is a large, two-headed Mystery Class dragon. Hideous Zipplebacks are sly and surprising, but certain noises can confuse them and cause individual ones to entangle their two necks. They made their debut in the first film, and has made frequent appearances ever since.

Official Description
"Of all the dragons that inhabit our world, one of the most unusual and dangerous is the Hideous Zippleback. The Zippleback is one of the largest dragons you may ever encounter. It's unmistakable with its twin heads. The heads are distinct, with separate thoughts and different personalities. Like most dragons, Zipplebacks can fly, but their wings are small and they spend most of their time on the ground. Zipplebacks are solitary, preferring to hunt alone. They come out after sundown, prowling dark forests for victims. The attack of a Zippleback is like no other. Instead of breathing fire, a Zippleback makes explosions. One head BREATHES gas, and the other head lights it."

- Dragonpedia

"This two-headed threat is the longest dragon and has the smallest wings & stubbiest legs. But the way it produces fire makes up for any physical drawbacks. While one head shoots out a flammable gas, the other ignites it with a spark—allowing for attacks from long distances. “It is based more on a Siamese cat combined with a devious snakelike quality."

- Dean DeBlois in an interview with USA Today.

"Gas + Spark = BOOM! This tricky and evasive 2-headed Mystery Class Dragon is double trouble... when it isn’t bickering with itself. The Hideous Zippleback's gas-and-spark combo makes this Dragon a powerful force in battle."

"The Hideous Zippleback is apart of the Mystery Class, as said in the Journal of Dragons. The rare and unique ability these dragons have is the, ‘Gas and Spark’. Which allows one head to produce a thick green gas in the air while the other head can create sparks in his mouth to light the gas on fire, to create a huge explosion. The Zippleback is known for its stealth and a decent firepower."

- School of Dragons

Development
The Zipplebacks' head, neck and tail movements were inspired by cobras, as they were 'fluid' and 'mesmerizing', says Simon Otto. Their posture and walking structure, however, resembles that of a Komodo dragon or a horned lizard.

Original concept art, such as Two Headed by Nico Marlet, depicted the Zippleback with three heads, and a flatter, more collapsible skull. Special attention was paid to the coloring palette, in which the combinations of yellow and red, purple and orange, and teal and orange, were tested.

"The modelling and rigging teams had more than twice the fun working on the build of this dragon: imagine what they thought when they were told this design "would have two heads and two long necks that should be able to zip together," recalls Head of Rigging Jeff Light."

- The Art of How to Train Your Dragon

The Zippleback is described to have 4,769 keyable animation controls, whereas humans only had 1,100.

Egg
In promotional material for the first movie, these eggs are described as containing buoyant natural gasses that are often mistaken for air bubbles. These bubbles give the surface of the egg a bumpy look full of craters. The eggs in School of Dragons look similar to those in the promotional material too. In Dragons: Rise of Berk, the egg doesn't have any bubbles or mark of their presence whatsoever. Instead the egg has a pattern of scales similar to the markings on the neck and back of a Zippleback. They come in a variety of colors.

Hatchling to Adult
The Hideous Zippleback is often described as one of the most unusual dragons in the world. This dragon has two long, serpentine necks with spikes on it. These spikes can 'zip' together, in order to create the illusion of one neck. At the end of the necks, are two short heads. The Zippleback has a large horn on its nose, and two thinner horns on top of its head. Like most dragons, they have yellow reptile-like eyes. The teeth in their lower jaw seem to be longer then the one's in the upper jaw, sticking out. They also have two tails, which can also 'zip' together. The end of the tail posses a fin-like structure on its tails. The official website stated that, thanks to its relatively short legs and wings, the Zippleback is a slow walker and flier. Despite this, Barf and Belch has been seen flying quite fast. Their legs possess short, but strong legs with four sharp claws. The Zippleback is probably one of the longest of the medium-sized dragons, if not the biggest.

Titan Wing
Titan winged Hideous Zipplebacks are rather colorful and has many different patterns on its body. Its body is greyish green and their wings have three main colors: There are a large amount of spikes added and their tail tip increased in size and are more of a diamond shape.
 * Blue with white spots
 * Purple
 * Dark Green

Babies' Abilities
As eggs, they have the ability to contain their special ability of defense is their buoyant gas.

While sometimes these babies can be fussy, they can benefit from having a close relationship with their siblings from having increased hunting and defense, with one head watching for prey while the other head makes sure the coast is clear. However, it is likely the heads take some time to learn to get along with each other.

Gas and Spark
"The Hideous Zippleback's gas-and-spark combo makes this Dragon a powerful force in battle."

- Dragons: Rise of Berk The head on the right side breathes a green, flammable gas, while the left head produces an electrical spark from its mouth to ignite the gas, creating lethal explosions, small fire bolts, or large fire 'walls' to contain their enemies. By itself, the gas can make a human disorientated if inhaled, as shown by Fishlegs. Zippleback gas can also be used to make anything that is covered by molted Changewing skin visible again.

Stealth
They can also use this gas in order to hide themselves, which makes them very stealthy. They use it to unexpectedly strike their victims.

Flaming Ouroboros Formation
The Zippleback's special ability is to release a large amount of gas, and then set themselves on fire. They bite their own tails and become a flaming ouroboros, which they can use to knock out enemies. It is likely they have to be taught how to use this ability, however.

Venom
In the movie, Fishlegs stated the Zippleback's venom is injected for pre-digestion, which may mean that they have a weak digestive system. However, the stats say that the Zippleback has no venom at all.

Speed and Agility
Despite the official website claiming Zipplebacks are poor fliers and walkers, Hideous Zipplebacks have shown to be quite agile and fast. This was demonstrated in the battle with the Red Death and later also multiple times in the series. Therefore, it is safe to assume that the Zippleback is actually a quite agile and flexible dragon, although nowhere being near the fastest.

Endurance and Stamina
Zippleback is able to endure the attack of a Typhoomerang and still able to get back to try to continue the battle, as they have a large amount of stamina on their side to continue long flights to catch up with other dragons.

Climber
Hideous Zipplebacks have shown to be great climbers as Barf and Belch have shown in the episode "We Are Family, Part 1" as they are able to climb terrains very well.

Hunting
These dragons are solitary hunters that prefer to hunt as ambush. Since these dragons have great stealth as they will use their gas to trap their prey in and able to do sneak attack. They even able to hunt well in the bushes in the forest as for ambush hunt.

Strength and Combat
Zippleback have proven to be very strong as they are able to tangle their necks together to carry weight of Gronckle. Fishlegs, Tuffnut, and Ruffnut without too munch difficulties. But single neck of Zippleback was shown by Barf that wasn't able to carry very heavy rider. They even showed some of their strength to hold their ground against Toothless.

Intelligence
While growing, hatchlings are stated in Dragonpedia to have high intellect and problem-solving abilities, such as having one head watch for danger while the other watches for food, or managing to solve complex problems such as one head scaring the prey into the mouth of the other head.

Barf and Belch have proven to be very intelligent at times. They knew to use the statue of the Eruptodon on Caldera Cay to stop the flow of the lava threatening to destroy the village. They also knew to use their distress call when Hiccup was in trouble as well.

Transmitting Information
They have a special ability to simultaneously transmit information to both of their brains. For example, if one head is covered up with a blindfold and food is stuck in front of the other head, both heads will start salivating at the same time, even though only one can actually see the food. With this special ability it makes it nearly impossible to sneak up on a Zippleback. The two heads, however, still possess their individual thoughts and different personalities.

Behavior and Personality
The dragon has two personalities and two minds, one in each head, and often different ideas, thoughts, and personalities causes the Hideous Zippleback's heads to argue with each other over what to do. This dragon reminds some Vikings of bickering siblings when they aren't running away from it. Occasionally the dragon forgets that it is a two headed dragon, and one head tries to go one way, and the other head tries to go the other way, this can be problematic. Even baby Zipplebacks fight over which direction to go or what to do.

It has been stated by Gobber that once this dragon is saved by a Viking, they must pay their long time debt. They are willing to do everything to show how grateful they are of their savior by giving them fish or affection. This could be another way for training a Zippleback or any other dragon species. As Barf and Belch have proven, they will even leave their old riders behind to stay with another for his entire life until they return the favor.

Weaknesses
The dual heads can be a vulnerability, as Drago Bludvist's forces were able to incapacitate a Zippleback by shooting darts into the neck of one head, knocking both heads out. The two heads have different personalities, and if they don't work together, it can be hard for them to do anything. They even slam into objects if both heads are not paying attention when chasing prey, as shown when a wild Zippleback chased Tuffnut into a tree. However, when Barf was stung by an immature Speed Stinger, Belch was unaffected and proceeded to drag around a paralyzed Barf who constantly emitted flammable gas.

Training
To train a Zippleback, you must feed both heads at once, then play with the dragon to keep them occupied. Another way to train one is to save a Zippleback's life. If this is done, they will be completely loyal to the person no matter what until they can repay the favor. This can likely be used to be train one as well.

In the Game, How to Train Your Dragon, feeding ham to a Zippleback will train it. No further instructions are given. According to the game, ham is a Hideous Zippleback's favorite food.

How to Train Your Dragon
Th first Zippleback is seen during Hiccup's opening narration, where he describes the Zippleback and one blasts a hut. During the gang's third test, they were pitted against a Hideous Zippleback. The dragon starts the drill with a bang, releasing gas into arena the moment the doors are lose. Amidst the fog, it slowly picks out the students. When they face the last pair, Hiccup and Fishlegs, Fishlegs pours a bucket of water on the head that gases, and the Zippleback attacks Fishlegs, who makes a prompt escape. The other head emerges from the fog, and Hiccup prepares to splash the head that sparks with water, only to miss hopelessly. Hiccup learns from Toothless that most dragons hate eels enough to actually fear them and uses this against a Zippleback to scare it back into its den during dragon training. At the end of the movie, a Hideous Zippleback (eventually named Barf and Belch) is flown by Ruffnut and Tuffnut. Each head seems to agree with one twin and they have appeared in almost every other episode since then.

Gift of the Night Fury
The Zippleback was one of the species that headed to the Rookery from Berk. A baby Zippleback was seen playing with two children when the dragons returned to Berk.

Book of Dragons
The Zippleback was introduced into further detail during this short. Bork chased his trusted sheep, Willie, into a cave that was unexpectedly a Zippleback's lair. The dragon caught Bork's attention and Bork pulled out a sword trying battling both heads. The Zippleback caused an explosion and defeated Bork. You may be able to befriend a Hideous Zippleback if you feed and play with both heads at once, keeping them occupied.

Season 2
Bucket and Mulch received a blue and green Zippleback, named Whip and Lash, during their recruitment in Team Astrid. They later then helped defend the Edge against Dagur's attack, and recieved the compliment from the twins, that they were like a better looking mirror.

Season 6
In the episode "A Gruff Separation", Ruffnut and Tuffnut take the Thorston Induction Trials. In the final task, the twins complete in getting a chest from a Titan Wing Zippleback's nest.

How to Train Your Dragon 2
A blue Zippleback was first seen getting its teeth cleaned at Gobber's. Later on, some were seen in Valka's Sanctuary. During the Battle of the Bewilderbeasts, captive Zipplebacks used the Flaming Wheel technique to knock out the traps and trappers.

How to Train Your Dragon
In this game, Zipplebacks can be trained by feeding it ham. There are both trained and wild Zippleback to fight throughout the game. Zipplebacks are also customizable - their head horns, wings, feet, spine protrusions, tail ends, and color can be changed.

DreamWorks Dragons: Wild Skies
Described as 'Double Trouble, Two Heads are Better than One', this dragon resides in Black Heart Bay. In this game, only one rider is required to properly control this dragon. Training this dragon unlocks the 'Doble Trouble' achievement.

Dragons: Rise of Berk
The Zippleback, as well as Barf and Belch, their mate and offspring, Exiled Hideous Zippleback and Whip and Lash became available in Rise of Berk. Their Titan form and battle form were also made available in the game.

School of Dragons
This dragon was also made playable, along with its Titan form which was adapted from the Rise of Berk's version.

Trivia

 * In School of Dragons, Tuffnut said that only a Zippleback can light the gas on fire, and that a Nadder can't do that. But in the second film it was shown exactly the opposite - after Barf and Belch covered the traps with gas, Stormfly set it on fire.
 * In Rise of Berk, the Hideous Zippleback breathes gas from its left head, and sparks come from its right head. In every other incarnation, gas comes from the right head, and sparks from the left head. It is possible that Zipplebacks can actually have either arrangement, as Gobber mentioned it was "tricky" to tell which head was the spark-igniting one.
 * Although the official website states that the Hideous Zippleback is not effective in flight because of its small wings, during the young Vikings' counterattack against the Red Death in the first movie, it's shown that the Zippleback (Barf and Belch) is agile, fast, and effective at flying.
 * It was believed that the Zippleback was unable to breathe gas and spark while in flight, but in the TV Series, Barf and Belch are seen to be more than capable to ignite and breathe gas without too much trouble.
 * The Hideous Zippleback resembles Zmey Gorynych, the Slavic Dragon.
 * The Hideous Zippleback's two heads working together is based on the proverb, "Two heads are better than one".
 * It's shown in a training addition to How to Train your Dragon (film) that Hideous Zipplebacks (and other dragons) have a sense of humor; when a Hideous Zippleback attacks Ruff and Tuff while the two twins fight, the heads grin at each other as the twins continue to fight dangling from the Zippleback's mouths.
 * According to the Rise of Berk mobile game, Zipplebacks have only one heart and thus, it is highly likely that they have only one set of internal organs, except for the brain.
 * The dragon stats say that the Zippleback is non-venomous, but Fishlegs says otherwise, once commenting that its fangs can inject pre-digestive venom into its victims.
 * The Zippleback's name is possibly derived from Zippo, a brand of lighter, which is fitting as one of the dragon's heads serves to light the gas produced by the other head. It could also be from zipper, as the dragon can link and unlink the spines on its neck and tail together.
 * Although this behavior was only seen once, when Barf and Belch approached Hiccup in the How to Train Your Dragon movie, they fanned out their wings, flapping them slightly and started aggressively hissing at him, which mimics the behavior of the Dilophosaurus in Jurassic Park when it fans out it's frill and growls to spit venom. This behavior is presumably done to make the Zippleback seem more menacing and larger than they appear. This display is never seen again.
 * In the early concept arts, the Hideous Zippleback had a frill similar to the Dilophosaurus'.
 * The film Wrath of the Titans references the Zippleback: one of the monsters Perseus fights is a two-headed Chimera, where one of its heads spits out flammable saliva and the other one ignites it with hot embers, and working together can produce bursts of flame, just like the Zippleback.
 * Zipplebacks only need one rider in Wild Skies, How To Train Your Dragon video game and School of Dragons.
 * Hideous Zipplebacks can reach 50-66ft long as shown from Barf and Belch in the Guide to the Dragon Book has stated.