Girl Hookfang is a female Monstrous Nightmare who was calling out for help from the nearest Monstrous Nightmare that was around. She managed to get Hookfang to help her protect her eggs from the Titan Wing Monstrous Nightmare. She was dubbed by Snotlout when he tried to get her away from Hookfang.
- "Things can get heated when Girl-Hookfang senses danger, especialy when she's protecting her eggs!"
In "Total Nightmare", Snotlout found Girl Hookfang when his dragon had been disappearing. He tried scaring her off with an electric eel, but then figured out that Hookfang had been trying to protect her from the Titan Wing.
She is an average purple and yellow Monstrous Nightmare.
Girl Hookfang is very protective of her eggs. She is shown to be quite aggressive towards those that come near her cave, but she is very friendly to Hookfang because he helped her protect her eggs from harm. Later, she even showed enough trust to allow humans to look at her hatchlings.
- It is possible that Girl Hookfang had a mate that was killed by the Titan Wing Monstrous Nightmare. She may have also had eggs through parthenogenesis. Either way, these reasons would explain why she was calling to another non-mated male Monstrous Nightmare to help her guard her eggs.
- According to Fishlegs, her mate was likely a rival of the Titan Wing Monstrous Nightmare, leading to him attacking Girl Hookfang's eggs.
- Girl Hookfang's colors are very similar to those of Fanghook and Cagecruncher. Her colors are also similar to those of the Monstrous Nightmare that Astrid trained on Outcast Island when she was pretending to be Heather.