Which of the short films contained in "How to Train Your Dragon" franchise is a 2010 animated short film by DreamWorks Animation?
How to Train Your Dragon (franchise):  The franchise also consists of four short films: "Legend of the Boneknapper Dragon" (2010), "Book of Dragons" (2011), "Gift of the Night Fury" (2011) and "Dawn of the Dragon Racers" (2014). Legend of the Boneknapper Dragon: 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".
Legend of the Boneknapper Dragon