The BoneKnapper will often go to extreme lengths to find the bones it seeks, hunting down the fragments for years. However, the dragon does has a docile side to its nature as well, as with most dragons around Berk.
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. The Boneknapper appeared as the main antagonist in The 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 appearence on a distant island after Gobber, along with Hiccup and his friends, set out to capture it. Hiccup realises that Gobber's belt buckle is the piece of bone that the Boneknapper wants, which is missing from it's 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.