In the film, like the other main characters' dragons, Hookfang was kept prisoner at dragon training and the top of the dragon training class would've had the 'honor' of killing him. Hiccup was given the chance and instead, tries to connect to him and show the Vikings that dragons are not monsters, but after an outburst from Stoick, he becomes startled and begins to attack Hiccup in defense, until Toothless comes and protects his friend from the much bigger dragon, having no difficulty in subduing the enemy. Later, when Hiccup is trying to get his friends to connect with the dragons and help fight the Red Death, Hookfang is the first one he brings out. Everyone is astounded by this, except for Astrid, who already knew what Hiccup was capable of.
Ironically, Snotlout is terrified enough to prepare a broken end of a spear as a weapon, in case Hookfang starts attacking, but Astrid nudges him to put it down. When Hiccup brings Hookfang closer to the others, he grabs Snotlout's arm so he can touch the dragon. Snotlout, obviously still frightened tries to resist, until Hiccup calms him and places his hand on his snout and he begins to growl in a purring manner. Snotlout's fear turns to amazement as he has made a connection, until Hiccup starts walking away to grab rope to "hang on" to the dragons, as the camera moves to reveal that the Gronckle, Deadly Nadder, and Zippleback are out of the cages, ready to be tamed. During the final battle of the Red Death, Snotlout is seen riding Hookfang.
When it is seen that Hiccup and Toothless have defeated the Red Death but Hiccup is no where to be found, everyone is upset. Toothless reveals that Hiccup is alive and everyone is overjoyed. Hookfang makes a brief appearance as he bows his head between two Vikings and is seen to make a "woo" sound with his eyes closed. The Vikings stare at the dragon in amazement. At the end, Hookfang roared in front of Hiccups house when he opened the door. Then Snotlout and Hookfang join the other dragons and trainers as they rode into the sky.
In this short film, Hookfang makes a very short appearance. He's seen along with Snotlout, pouring water on Gobber's house, in an effort to put out the fire. Other than this, Hookfang did not make any further appearances in the short film.
During his first Snoggletog with Snotlout, he becomes a father. He's even the one to fly Hiccup back home with the other dragons and their hatchlings. When they get home and land, Snotlout runs over and hugs his snout, as they are both ecstatic to see each other. At the Snoggletog party, Snotlout is seen playing with one of his children.
This special was shortly after Silent Sven had broken his silence. While the teens got older as we see that Hookfang had a competitive side just like Snotlout. As he was able to successfully catch the black sheep before Toothless. Later, Hookfang and his rider caused an accident with Astrid by slamming themselves into each other which caused Astrid to break her arm. Hookfang was very eager to catch the regular sheep before Toothless could get it in the sea but was unsuccessful. Until the flash back was over he sees his rider being upset about not making to the dragon race so he showed his concern to his rider. Until his rider was excited about his new invention, the sheep launcher, Hookfang was happy for him and was getting ready for another race with other dragons and their riders.
In "Viking for Hire", Hookfang begins behaving erratically and damages some of the Village buildings by thrashing around. He also becomes somewhat aggressive. Snotlout is unable to get through to him. Hookfang's behavior is so bad that Toothless fights with him. Gobber, who is struggling to find his own place in post-Dragon War Berk, is seemingly asked by Stoick to dispatch Hookfang, as he was too dangerous. However, just as he was about to presumably land a killing blow, Gobber saw the source of Hookfang's problem - a bad tooth. Gobber instead yanked the painful tooth out, relieving Hookfang of his pain. The dragon then returned to normal behavior. This led Gobber to find a new pursuit other than making dragon-killing weapons: dragon dentistry.
In "The Terrible Twos", Hookfang continues his joking stubborn behavior with Snotlout, by flying him through trees in Berk's forest, and taking him on an unexpected wild flight when they were demonstrating dragon flight to the baby Typhoomerang named Torch.
Hookfang is blames for the destruction of the Great Hall and is banished from Berk to Dragon Island along with the other dragons, in "In Dragons We Trust". In fact Mildew framed him, as well as Barf and Belch and Toothless in order to get them evicted.
While the dragons are pushed out of Berk, Alvin the Treacherous attacks the village looking for the 'Dragon Conquerer' in the episode "Alvin and the Outcasts". Hiccup convinces him to take him to Dragon Island. Stoick and the other Dragon Riders follow by ship. They retrieve their dragons and force a show-down with Alvin and his men. Stoick allows the dragons to return to Berk, much to Mildew's dismay.
"Defiant One" He also seems to take callous pleasure in making Snotlout scream when they are out for a flying ride. He disobeys Snotlout most of the time, however, Snotlout says to go North when Hiccup says to go South. Wanting to keep on go with the others, Hookfang doesn't respond until Snotlout looks his dragon in the eye and says, "Hey, you work for ME!" Later, Hookfang is seen carrying Gobber as an attempt to save Snotlout, Hiccup, and Toothless from Outcast Island. Hookfang also gets distracted easily, like chasing a seagull or watching a leaf fall. He may have learned this behavior from Snotlout, as well as his rebellious, deliberately disobedient attitude towards his rider, which mirrors Snotlout's attitude towards Hiccup in the academy.
"Race to Fireworm Island" Hookfang was shown to be train very hard by Snotlout as he was told by his father "Rest is for the weak" made his dragon sick when Hookfang's flame goes out due to exhaustion, it put his life at risk. It's shown that Hookfang did really care for Snotlout, proving this when he throws the Fireworm gel instead of consuming it, to save Snotlout from getting killed by the Fireworm Queen when he stole Fireworm gel to save Hookfang's life.
"Fright of Passage" Hookfang showed a definite amount of impertinence towards Snotlout, as evidenced by the look he gave Snotlout as he entered Ruffnut and Tuffnut's secret hideaway.
Hookfang was in contact with dragon root that cause him to become aggressive to attack Stormfly which later he was switch to have Astrid as his rider temporary for a day. Which he shown off his abilities to Astrid that she shown to enjoy. Hookfang shown off his new hidden ability thanks to Astrid help finding out he has powerful attack to create Wing Blast. As he was shown to use this attack to take down Barf & Belch.
"A View to a Skrill, Part 1" Hookfang then assisted in looking for the Skrill and later on the twins.
"Cast Out, Part 1 and Part 2" He and his rider disobey a direct order that causes Astrid to get hurt. When suspended from the Academy by Hiccup, they leave Berk to find a island of their own to claim is their Snotloutland. As Hookfang shown to use flamethrower on different objects to claim is theirs. While they were investigated a outcast ship they met the Screaming Death.
As Hookfang saved his owner but failed when he got attack by the by the large dragon that he was trying to wake up his rider from being unconscious that he was upset thinking his rider was killed but shown to be safe thanks to the former leader of the outcast. He gave the former outcast leader lift to Berk. Later in the second part he and Snotlout defeated Dagur the Deranged by creating Wing Fire Blast attack that he even saved the Screaming Death mother from harm.
"Big Man on Berk" Hookfang was briefly offered by Snotlout to give to Fishlegs when he was Bonecrusher. As he was showing how powerful Monstrous Nightmares were, Bonecrusher said Monstrous Nightmare weren't that great to him. Hookfang even manage to save Snotlout from drowning and the Scauldron as he was promised to never be given away.
"Total Nightmare" Hookfang was shown to help a female Monstrous Nightmare as he was answering her distress call. He protected this female dragon from the harm of eels and the Titan Wing Monstrous Nightmare; this dragon is much stronger and more aggressive. Hookfang made the other dragon riders believe he was going feral as he was shown to be territorial towards Snotlout.
"Night of the Hunters, Part 1 and Part 2" Hookfang then attacked Ryker Grimborn's ship and his dragon hunters to rescue Stormfly. However, when they attempted to free the riders and their dragons, Hookfang was then hit with the Hunters' arrows. He and Snotlout were then saved when Toothless grabbed his tail and flew away. The next day, Hookfang recovered. They then went to the Screaming Death's Island.
There, Hookfang and Toothless were given armor made from the Screaming Death's scales. Together, Hookfang and Toothless were able to rescue the riders and their dragons.
"Snotlout Gets the Axe" Hookfang then assisted Snotlout in retrieving the Jorgenson Ceremonial Axe from the Armorwing, Bandit. At first he was unsuccessful. However, after Snotlout and the other riders brought the Smothering Smokebreaths to free the axe, Hookfang then defended the Armorwing against the Smokebreaths. Hookfang and the other dragon then gave it metal.
"Edge of Disaster, Part 1 and Part 2" Hookfang then went with Snotlout, Hiccup, Fishlegs and their dragons to rescue Trader Johann from the Dragon Hunters. However, they saw that it was actually a pack of wild dragons from Forest Island. At first, they were able to fight off Scardian and his pack, until Fishlegs was taken.
Hookfang and Snotlout were able to rescue Fishlegs and make friends with Scardian's pack. Together, they were able to force Ryker's hunters and Dagur's Berserkers to retreat.
"Follow the Leader" After the Twins used up all the Nightmare gel, Hookfang and Snotlout refused to give them Hookfang's gel without paying for it.
"Turn and Burn" Hookfang then assisted Snotlout, Stoick, Hiccup and Toothless in searching for Spitelout. However, when they got to Storehouse Island, Hookfang, along with Snotlout, Hiccup and Toothless were then caught in a trap. They then came under attack by a Singetail. They were then saved from it by Spitelout and Stoick then released them from the trap. Together, they then tried to drive the Singetail away from the island to no avail. When more singetails arrived, Hookfang and the others then abandoned the Island.
"A Grim Retreat" Hookfang, the other dragons, and their riders then went the Island of Friga for a vacation. However, Hookfang and the other dragons were then infected with Grimora leeches. However, Snotlout was able to get Hookfang into the salt water.
"To Heather or Not to Heather" Hookfang then took part in defending the Nadder migration from the Dragon Hunters. However, he was caught by their steel ropes. However, he and Snotlout were then rescued by Heather and Fishlegs.
Hookfang is shown to have three barbells under his chin, showing that he has aged. His color of his skin became much brighter of scarlet and lost his stripes, become dark spots. He was able to use his tail whip on Meatlug to release the sheep so Snotlout can have it. He is even shown to grin at her and her rider. He has been seen attacking Drago Bludvist on sight, trying to burn him. However, Drago was able to break him using his knowledge of dragons and his enslaved bewilderbeast. He was then freed by his rider and fought Drago's army at Valka's Mountain. However, Hookfang then came under control of Drago's Bewilderbeast and went with him back to Berk. However, like all dragons, he was overjoyed to be reunited with Snotlout and bowed down before Toothless as the new Alpha dragon.
When Snotlout was launced into the air by a Thunderclaw, Hookfang refused to catch him, letting his owner fall on the ground.
On their way to Nepenthe, the riders are accompanied by Tidal Class dragons offering tribute to their new alpha. Hookfang is annoyed by Snotlout, who gives him nicknames, like Hooktraitor or Looserfang, for not catching him earlier.
On the island, Hookfang relaxed un the hot pools, along some other dragons, instead of staying focused on the task.
At dinner, he, along the other dragons, began wating all the food on the table. They then collapse and are all captured by Calder and his men.
After Hiccup escapes, he brings all the dragons, including Hookfang and the riders prepare to leave the island. However, before they do that, some Foreverwings wake up and start destroying the village. Hookfang helps by burning the soldiers' weapons, preventing them from hurting the dragons. After Hiccup defeats Calder, Hookfang arrives at the scene and Snotout states that his dragon is homesick for Berk.
The next day, Hookfang is seen listening to Hiccup speech to the village and later knocks Snotlout off his feet.
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