While trying to relocate a Scauldron, Fishlegs develops a rash and sneezing fit that causes a lot of problems, so after a round of... lets call them tests, the twins deduce that Fishlegs has developed Adult-Onset Allergies and is now allergic to Meatlug. The teens go to Gothi in hopes of getting a cure, but Gothi says the only thing they can try is hypnotism. After agreeing, Fishlegs quickly falls under Gothi's hypnotism and Hiccup convinces him he is no longer allergic to Meatlug, but before Fishlegs can be awoken Snotlout decides to make him into the greatest Viking who has ever been seen. Upon awakening, Fishlegs no longer recalls his normal identity and is convinced that he is a viking hero called Thor Bonecrusher.
- Adult Fear: Fear of Meatlug being hurt is what snaps Fishlegs back to normal.
- Homoerotic Subtext: Snotlout has a huge crush on Bonecrusher, and it is not subtle.
- Jerkass with a Heart of Gold: Bonecrusher is a huge jerk with a ego the size of a Scauldron, but he is also very heroic in that he saved a baby, fed a starving man, and calmed a distressed calf.
- Never Mess with Granny: When Hiccup and co. return to Gothi in hopes she can reverse the hypnotism she feeds Bonecrusher a potion that makes him instantly start puking his guts out. When asked if it worked Gothi said it wasn't a cure, she was just getting back at him for breaking her staff.
- Red Herring: Fishlegs is actually allergic to Gobber's earwax, which Gobber has been using to wax Meatlug's saddle.
- Shipper on Deck: Astrid finds Snotlout's crush on Bonecrusher hilarious, and frequently mentions that he is in love with him.Hiccup: What was Snotlout thinking?
Astrid: He wasn't! He's in lo-o-ove!
- Something Completely Different: This episode has very little to do with the ongoing plot, and takes place entirely in Berk with no acknowledgement of the gang haven't even gone to Dragon's Edge in the previous episode and they are back there in the next.
- Unreliable Narrator: Bonecrusher's stories portray him as much more cool and competent than he really. He also gets background details completely wrong; one particular story had all the riders huddled in fear on Toothless while the other dragons were nowhere in sight.