Legend of the Boneknapper Dragon is a 2010 animated short film by DreamWorks Animation that is a sequel to the feature film, How to Train Your Dragon.The short was originally broadcast on television on October 14, 2010 on Cartoon Network, and released as a special feature on Blu-ray and double DVD edition of the original feature film on October 15, 2010.The film follows Hiccup and his young fellows accompanying their mentor, Gobber, on a quest to kill the legendary Boneknapper Dragon.