In Dragons: Riders of Berk
In the TV series, Snotlout is one of the main dragon trainers. Like Ruffnut, he has a different voice actor. His dragon, Hookfang, often disrespects Snotlout, and almost never follows his commands. When the dragons are exiled, Hookfang is the only one to run away. Despite this, Snotlout has shown that he cares for Hookfang, being particularly relieved when the dragon - who had seemingly gone mad and was rampaging through the village, to the point where it appeared that Gobber would have to kill him- turned out to merely be suffering from toothache (although he attempted to pass off his enthusiastic hug of Hookfang after the tooth was taken out).
Snotlout in the TV Series, sad that Gobber is going to kill Hookfang
When Hiccup, Toothless and Snotlout were stranded on Outcast Island, Snotlout managed to successfully hold his own against an adult Outcast in a fight when armed only with a metal rod (although he still required Toothless's help to defeat his opponent). Snotlout has proven that in some ways he can back up his boasting. He is usually an able fighter (when not trying to impress the ladies), and he is in very good physical shape. He wins all the Viking based Thawfest games with relative ease. Only when dragon events are introduced does he struggle. He still wins the Thawfest games, but only because Hiccup allows him to. Even with Hiccup's good sportsmanship in the end, Snotlout remains completely ungrateful and gloats in his victory.
The stranding on Outcast island forced Hiccup and Snotlout to work together. It was a seriously rough time because both boys were rivals, and Snotlout was intentionally provocative. Eventually Snotlout lost his temper enough to vent hugely hurtful insults at Hiccup and to really unintentionally reveal a slight twinge of envy over Hiccup's popularity and courage. But even after all their fighting, Snotlout was quick to come and aid in Hiccup's rescue. He and Toothless worked well together as a team and saved Hiccup from the Outcasts who had captured him. The episode ended on a very high note for Hiccup and Snotlout with both boys seeming to gain a much greater appreciation for one another.
In Dragons: Defenders of Berk
In the Season 2 episode Race to Fireworm Island, a softer side of Snotlout is demonstrated. Since the Outcast attacks, Snotlout has been training Hookfang constantly, refusing to give him a break as he believes "rest is for the weak", which his father had taught him. However, he works Hookfang so much that Hookfang begins to lose his flames and is dying from exhaustion. Though Snotlout tries to hide it, it becomes apparent that he cares for Hookfang as he begins to cry and worry for him. He was also shown to be concerned when his father told Snotlout that "if our sword is not cutting properly, we sharpen it. But if our sword cannot be sharpened any longer, we get a new one", insinuating Snotlout to get a new dragon if Hookfang doesn't recover. When the Bork papers tells of Fireworm Island, Snotlout rushes over with the rest of the Dragon Training Academy to figure out a solution to Hookfang's exhaustion and discovers a cave of Fireworms and fire-combs. He is willing to risk his life to steal a piece of fire-comb and incur the wrath of the Fireworm Queen in the hopes that having Hookfang eating the fire-comb will help him recover his flames. Hookfang ultimately gives the fire-comb back to the Fireworm Queen to protect Snotlout from her wrath, and the Fireworm Queen restores his flames. Snotlout rejoices and decides to take it easy until Hookfang fully recovers (stating that his dad knew nothing about dragons) but Hookfang begins to flip Snotlout in the air, demonstrating that he has fully recovered.
In Free Scauldy, Snotlout spends most of his screen time flirting with Astrid; however, it seems that the point had been partly get a rise out of her, as he appears both disturbed and grossed out when she pretends to flirt back in an overly sweet manner.
In Cast Out Part I Snotlout, despite hearing Hiccup command a retreat in the practice drill, orders Hookfang to shoot gobber's catapult. The catapult malfunctions and shoots at Astrid. After landing, Snotlout shows no regret in almost killing Astrid and doesn't apologize. When Hiccup "grounds" him, he shows anger and flies off on Hookfang to an island and is attacked by the Screaming Death, and gets knocked unconscious. The villagers celebrate when they assume he is dead, but groan when Snotlout awakens briefly to claim he had captured Alvin the Treacherous.
In Cast Out Part II, Snotlout yet again defied Hiccup's commands and repeated his mistake he made in Cast Out Part I, but freeing the Screaming Death's mother from Dagur in the process. He later admitted to Hiccup that he was being reckless. Hiccup assured Snotlout that this time, he was doing the right thing and cancelled his suspension from the Dragon Academy. The two boys soon shook hands and became friends in the end.
How to Train Your Dragon 2
In this movie, Snotlout has apparently gave up on Astrid, as she is officially with Hiccup, and started to hit on Ruffnut along with, for some weird reason, Fishlegs. He has grown up, looking more like his Father, and seems to be a bit less arrogant and obnoxious.
