When Fishlegs discovers an extremely rare Seashocker in Edge Cove, he is extremely interested in studying it; but keeping it there is causing the Seashocker more harm than good.
Tropes:
- Be Careful What You Wish For: The twins didn't like the others turning Loki Day on them.
- Big Damn Heroes: The rest of the Seashocker pod shows up at the end to scare away the Scauldron pack, saving the main Seashocker from being eaten.
- Cassandra Truth: Nobody believes Fishlegs about the Seashocker at first, because either they think it's a prank, or they think he was hallucinating.
- Continuity Nod: The episodes-old falling-fish-in-Hiccup's-hut gag makes a reappearance.
- Et Tu, Brute?: Tuffnut betrays his sister in their prank war against the others.
- Hold the Line: The riders end up protecting the Seashocker from hungry Scauldrons, which is made difficult due to being flying dragons trying to fight underwater dragons.
- The Millstone: The twins spend the entire day pranking the others, even during critical moments.
- Not So Above It All:
- Hiccup and Astrid book-end their Loki Day revenge on the twins by the end of the episode.
- In a minor example, Fishlegs confesses to having stolen Snotlout's favorite axe when spooked by the Seashocker, and sheepishly covers up this fact when he goes to show the other riders the dragon.
- Practical Joke: All over the place, because it's Loki Day, and the twins want to make it the funniest one ever.
- Shock and Awe: The Seashocker's abilities. And the title.
- Squee: Hiccup and Fishlegs go right into geek mode when they realize they have a rare dragon in the lagoon. Snotlout and the twins do not share the sentiment.
- Tempting Fate: Snotlout is still set on the idea of Fishlegs trying to prank everyone with an imaginary creature, when the Seashocker jumps out of the water and zaps him.
- What the Hell, Hero?: Although Fishlegs just wants to study the Seashocker, he causes it a great amount of stress by trapping a deep water dragon in a shallow water cove, and also leaves it vulnerable to predators; something Fishlegs keeps ignoring until the situation gets really bad.
- Your Princess Is in Another Castle!: The riders get rid of the rock wall sealing the cove, but the Seashocker goes right back in due to the appearance of a pair of Scauldrons.
