Bonesnarl was one of the armored dragons in Drago's dragon army. He likely participated in the battle at Valka's Mountain. After Toothless became the new alpha, Bonesnarl switched sides and joined him. Bonesnarl was essential in the final fight, as he blasted off Drago's false arm, giving him only one arm to work with. After Drago was defeated, Bonesnarl was the only dragon from his army that refused to take off his armor. When Snotlout tried to take the armor off, Bonesnarl briefly rampaged through Berk before being calmed down by Hiccup and Toothless. He now works in Gobber's workshop, helping to calm down the Scuttleclaws when they get too rambunctious and wake up Grump to light the forge.
Due to the fact that he was not taken care of as part of Drago's dragon army, Bonesnarl is gray in color. He also has blue spots on his wings and tail. Since "joining" Drago's army, he wears silver dragon armor that he refuses to have removed.