Dragons: Race to the Edge - Season 6 Episode 4

After learning his ancestors were dragon hunters who killed off the Dramillions, Fishlegs sets out to Dramillion Island with Astrid (against Hiccups wishes) to find and help protect the Dramillions from harm. Before setting out, he remembers his dragon scouts are coming and leaves the twins to look after them. After arriving, he immediately finds one and tries to train but discovers it is very aggressive and has the unusual ability to mimic the fire blasts of other dragons, such as a Gronkle's lava blast and Nadder's magnesium fire breath. While searching the island for more, they discover a group of hunters, who are following the teachings of his ancestor, Ingard Ingerman in trapping Dramillions and using them to help train new recruits. When the hunt begins, Fishlegs and Astrid combine Meatlug and Stormfly's fire to destroy the shackle that grounds the Dramillion. Though they realize that they won't have enough time to save them all, the Dramillions learn the technique to destroy the shackles themselves and are able to free each other. While this is happening the twins and Snotlout teach the scouts some of their 'ways' and lose track of them.