Screaming Death

The Screaming Death is a new dragon (sub-species to the Whispering Death) that appeared in Tunnel Vision, the fourth episode of the Defenders of Berk season. According to Fishlegs, it is not documented in the Book of Dragons, but is dubbed by Tuffnut.

Description
The Screaming Death appears to be a mutated, albino Whispering Death. It is white in color, has large red eyes, a longer and more massive body and tail than a normal Whispering Death. It also has three rows of teeth, but they are aligned differently than those of the Whispering Death, set in a chin reminiscent of the Seadragonus Giganticus Maximus. Like the Whispering Death, it can tunnel underground, and can shoot spikes from its body, although the tunnel it creates and the spikes it launches are larger. But unlike the Whispering Death, the Screaming Death shoots explosive balls of fire not unlike a night fury but similar to a mortar. During this, it also releases fire from behind its frill. Judging by the massive size of what is apparently a hatchling, this albino giant is probably one of the biggest dragons of them all, seemingly outsizing the Red Death a few weeks after it's birth. It is attracted to sunlight as opposed to having an aversion, as Whispering Deaths do. It also differs from Whispering Death as it tunnels are so large that they can cause islands to sink.

The Screaming Death gets it name by its incredibly disorienting roar that can affect the flight of other dragons. It is also relatively intelligent, as it did not fall for the refection off Hiccup's shield a second time.

Defenders of Berk
In the episode The Iron Gronckle, Savage and his fellow Outcasts return to Berk to check on the infant Whispering Deaths that have hatched in the caves beneath the village. Many egg shells are scattered along the cave floor, but much to Savage's surprise, one egg shell is truly massive. The hole left in the ceiling from the infant as it burrowed out is nearly the size of an adult Whispering Death tunnel, but this creature has just hatched. It can be assumed that this was the egg of a Screaming Death, and as Savage and his men retreat from the cave, the Screaming Death's roar can be distinctly heard echoing through the cave.

The Screaming Death first appeared in the episode, Tunnel Vision as the leader of the Whispering Deaths. It attacked Berk along with the hatchlings. Hiccup discovered the Screaming Death was attracted to the light off Hiccup's shield and used it to lure the dragon into ramming into one of the rock pillars. Its wing was injured from rocks falling on it. The Whispering Deaths take the Screaming Death away from Berk and nurse it back to health. However, Hiccup is concerned that the Screaming Death will return, noting that Whispering Death hatchlings are very territorial of their birthplace.

The Screaming Death, which did indeed get bigger, returned in Appetite for Destruction where it was sinking the other islands that dragons lived on. It made it to Dragon Island, and would soon reach Berk afterwards. Hiccup tried to distract it with his shield again, but it ignored the light. Fishlegs rounded up the dragons that lived on the islands the Screaming Death destroyed to fight it off. After being defeated, the Screaming Death left Dragon Island, but Hiccup is sure it will return.

Trivia

 * The Screaming Death seems to be the first dragon in the series to be a sub-species of another dragon.
 * The Screaming Death's fire breath is very similar to a gun, as it fires small shots in quick succesion and its frills flash with each shot which would be comparable to muzzle flash.
 * The Screaming Death is a Boulder class dragon, like the Whispering Death.
 * The Screaming Death's egg resembles a Whispering Death's egg, but larger in size.  Either the Outcasts were truly stupid and didn't register that one of their own eggs was much bigger to begin with, or the Screaming Death had been on Berk all along and would only hatch if there were more Whispering Deaths present than had previously been available.
 * The Screaming Death is the third dragon that wasn't in the Book of Dragons (other than the Red Death and the Typhoomerang). This is because the Screaming Death is a rare mutation of the Whispering Death.
 * The Screaming Death is attracted to bright light, unlike the Whispering Death.
 * The scream of the dragon disorientates most dragons, but appears to attract Whispering Deaths.
 * From the relationship shown between The Screaming Death and The Whispering Deaths present, the Screaming Death is presented as an "alpha-male" (presuming The Screaming Death was male) to the group, because of it's sheer size and power. The Screaming Death's scream attracts Whispering Deaths to it, the Whispering Deaths willingly carry it when it injures its wings, and the Screaming Death is brought food rations by the Whispering Deaths. Whether or not this was an instinctive relationship between the two species, an instinctive response for Whispering Deaths amongst their pack or a single example of dominance from the one Screaming Death is unknown.
 * Tuffnut came up with the name Screaming Death.
 * Due to the fact that the Screaming Death and the Whispering Deaths just hatched from their eggs for a few weeks by the time of Tunnel Vision, it is possible that like the Whispering Deaths, the Screaming Death is not yet fully grown. If that is true, then the Screaming Death will be even bigger if it makes more appearances in the upcoming episodes of Defenders of Berk.
 * In Tunnel Vision, Fishlegs describes the Screaming Death as a titan wing, this could mean that the Screaming Death has done its 5 stages of growth. This would be possible if the mutation affected the Screaming Death's growth.  If its true there could be another stage or stages other than egg, tiny tooth, short wing, broad wing, and titan wing.
 * According to Hiccup, the Screaming Death only hatches once every hundred years.

Differences to the Whispering Death

 * The Whispering Death is dullish green and grey, when the Screaming Death is white.
 * The Screaming Death seems to be able to withstand sunlight as it chases Hiccup and Toothless in broad daylight, while Whispering Deaths are normally scared of the sunlight.
 * The Whispering Death's eyes are white, while the Screaming Death's eyes are red.
 * The Whispering Death's teeth are yellow and are different sizes. The canines are twice as big as the other teeth (possibly bigger than the Screaming Death's). The Screaming Death's teeth are white and equal in sizes.
 * The Whispering Death's inner teeth are from left to right. The Screaming Death's inner teeth are from front to back.
 * The Whispering Death's mouth is bigger and has barely any chin. The Screaming Death's mouth is like many other dragons (unlike the Whispering Death's, which is shaped like an oval if you look from the front) and it has a large chin.
 * The Whispering Death shoots rings of fire. The Screaming Death shoots combustive fireballs.
 * The Whispering Death create whispering sounds that agitate dragons. The Screaming Death create screams that disorientate dragons.
 * A Thunderdrum can stun the Screaming Death but the Whispering Death isn't too vulnerable to Thunderdrum attacks.