This could mean that he was intelligent enough to figure out that she only hit him in order to rescue Heather's parents. However, he is also shown to be forgiving, seeing as how he later rescued her from Alvin the Treacherous. In fact, Astrid only succeeded in training him by displaying her dominance over him and pushing his horns to the ground, in a maneuver that calms all Nightmares. He was also upset and confused from having been caged on Outcast Island. Like most Monstrous Nightmares, he is hot-tempered and easy to anger, which was demonstrated when Astrid Hofferson tried to train him, and when she hit him in order to make him rear up and create a diversion. This ferocious and menacing dragon is feared for its astonishingly high speed attacking skills, and its ability to set itself on fire using the Fire Jacket tactic. His neck and wings are a darker shade of purple, whilst his snout fades into a yellow coloring and his underbelly is pale pink. Color Monstrous Nightmare True to its name, Hookfang is a monstrosity that is more than capable of making life a living nightmare for most Vikings. This Monstrous Nightmare is pale magenta, purple, and yellowish orange in color. He returned at the end when Alvin was about to throw Astrid off a cliff and saved her. When Alvin brought out Heather's adoptive parents, she, after apologizing, punched the Monstrous Nightmare's nose so he would flame up and attack the Outcasts. He became relaxed and bonded with Astrid. Astrid then remembered how Snotlout pinned Hookfang's horns to the ground to calm him down, and did the same to the fiery reptile. This just made the dragon angry and he flung her off. Astrid then tried a direct approach by grabbing his tail. She first tried to approach him slowly, but he "flamed up", knocking her back. He was the dragon chosen for Astrid to train, who was disguised as Heather and was hoping for a Deadly Nadder. During the events of "Heather Report, Part 1" and "Heather Report, Part 2", the Outcasts were trying to train him, but with no visible results.