Boneknapper

The Boneknapper is a species of dragon thought to be almost mythical by Vikings due to its rare nature. As its name may suggest, the Boneknapper spends its time scouring the land for pieces of bones in order to create the perfect armor for its body. Sometimes, this bone armor can be essential for the dragon to perform basic actions, such as roaring. The Boneknapper will often go to extreme lengths to find the bones it seeks, hunting down the fragments for years. However, the dragon does have a docile side to its nature as well, as with most dragons around Berk.

It is 24 metres (79 feet) long.

Description
A member of the Mystery-class, Boneknappers are built in a similar birdlike manner like the Deadly Nadder, albeit much larger. Their natural coloration seems to be a dull olive-green, though it can hard to see under their armor of bones.

Unlike most dragons, which have hard scales to protect themselves from enemies, Boneknapper scales are thin and soft. To counter this weakness, Boneknappers cover themselves in the bones and horns of dead dragons and other animals.

In How to Train Your Dragon
The Boneknapper makes a brief appearence in the How To Train Your Dragon film. After Dragon Training, Hiccup reads through the Dragon Manual in order to find information on Night Furies and ends up finding a page about the Boneknapper as he flicks through the book.

In Legend of the Boneknapper Dragon
The Boneknapper appeared as the main antagonist in Legend of the Boneknapper Dragon, a 15 minute short created for the release of How To Train Your Dragon on DVD. Originally having hunted down Gobber The Belch since his teen days numerous times, the dragon made its first physical appearance on a distant island after Gobber, along with Hiccup and his friends, set out to capture it. Hiccup realizes that Gobber's belt buckle is the piece of bone that the BoneKnapper wants, which is missing from its neck. Reluctantly, Gobber gives the piece of bone back to the dragon, where it suddenly becomes quite docile and playful. As a thank you, the Boneknapper lets Gobber, Hiccup and the others ride on its back to get home.

Trivia

 * The Boneknapper is one of two dragons that have been doubted of existence. Many Vikings believed there was no such thing as the Boneknapper. The other is the Smothering Smokebreath.
 * Without their armor, they somewhat resemble a cross between a Nadder and a Scauldron.
 * To train a Boneknapper, one must give it whatever it desires. It will then become like "...an overgrown puppydog."