Smothering Smokebreath

The Smothering Smokebreath is a new species of dragon that is only slightly bigger than the Terrible Terror. It appeared in episode 17 'Breakneck Bog' in Dragons: Riders of Berk.

Description
It can breathe off smoke from its mouth to hide itself from enemies or victims. Due to this ability, it was thought to be some sort of a "Fog Monster" and became legendary, to the point that, even though the Book of Dragons had info on it, Fishlegs believed it was just a myth. It is classified as a Mystery class dragon. Although it usually breathes smoke, it can breathe a rather hot fire, since it is able to meld metals in a matter of instants. A large swarm can appear as a large smoke-cloud. A group of them lives in caves on an island called "Breakneck Bog" (which is comprised of five islands that look like a hand, with their home being the thumb).

Smothering Smokebreaths have the peculiarity of collecting treasure and 'shiny things' to meld them together in their nests in order to defend themselves from other dragons. They often go to extreme lengths to collect treasure, as shown when they all formed a smoke cloud and chased the riders for their metallic things. Another one of their traits depicted in the Book of Dragons is that they are very territorial.

They hunt in complete stealth: concealed by their smoke, they surround their prey and close in until it can't see anything anymore, then they attack.

In Riders of Berk
The Smothering Smokebreath appeared in the episode Breakneck Bog, the bog is believed to be haunted by some kind of a "Fog Monster". The riders find Trader Johann unconscious on a wood. He says that he is attacked by the Fog Monster. Then they investigate the bog where they discovered Trader Johann's ship but the dragons cannot land there due to its unstableness. After the ship falls down the Fog Monster chases the riders and their dragons. They are revealed to the Smothering Smokebreaths after the dragons used their wings to clear the smoke. Then the Riders and their Dragons retreated.

A little while later they see the Dragons welding metal objects together with their fire to built the nest and Hiccup's gift is also seems to have taken into the cave. Fishlegs says they do this to protect themselves from larger dragons. They used Snotlout's shiny gold necklace to distract the Dragons while they took the gift. The dragons chased them and the Riders dropped all of their metal objects which the dragons took and went back. But one dragon attacked Hiccup but Fishlegs attacked it and made it retreated but is still feared of it. Then the Riders and Dragons returned safe to Berk.

Trivia

 * The Smothering Smokebreath is one of the mystery class  dragons in Wild Skies along with the Changewing.
 * It was first speculated to be in a Halloween episode, but it is not.
 * Many new dragons were revealed in the movie Book of Dragons, but apparently the Smothering Smokebreath was created along with Riders of Berk  just like the Typhoomerang and the Fireworm.
 * The Smothering Smokebreath is similar to a bat and a magpie combined, because a bat likes to live in caves and in large groups, and a magpie likes to collect shiny objects to build its nest.
 * The original picture of the Wild Skies Smokebreath looks much like a Monstrous Nightmare, but when the dragon was released in the game the image in the book was changed to match the dragon. It is possible that this had been a concept art but that the designers decided to change it because it was so similar to the existing dragon.
 * It is similar to the Terrible Terror as they travel in packs, small size, and they carry away objects together. This is seen when two of them try to carry away Tuffnut. They appear to be very social.
 * Despite a whole group of them appearing, t he Smothering Smokebreath is the only known species with no diferences in color.
 * Smothering Smokebreaths are one of only two dragons that don't have a horn or horn-shape on their nose. The other being the Night Fury.