Three new Thunderdrum babies emerge on Berk, to Hiccup's delight. When the dragons prove untrainable, however, except when Thornado is around, the riders have to go to desperate means to Shoo the Dog.
- Badass Adorable: Subverted with Bing, Bang and Boom. Although they contain a lot of firepower, erm sound power, they're outclassed when facing older wilder dragons.
- Foreshadowing: Training the three young Thunderdrums turns out to be impossible — baby dragons don't listen to anyone.
- Hollywood Tone-Deaf: Stoick doesn't enjoy Fishlegs's singing that is being used to test out a listening device.
- Killer Rabbit: The three babies, and why they can't stay on Berk. They like blowing up stuff and tormenting the sheep.
- Papa Wolf: Thornado when other wild dragons threaten the babies.
- Put on a Bus: Stoick frees Thornado so that the latter can take care of te babies and protect them until they grow up.
- Shoo the Dog: The riders end up having to do this with the three dragons. Then they realize why the babies came to Berk; wild dragons were attacking them.
- The Last of These Is Not Like the Others: The twins name the babies Bing, Bang and Lloyd. Hiccup for "Lloyd" suggests the more fitting "Boom".
- Took a Level in Jerkass: Stoick to a minor extent, where he claims that Thornado is not a babysitter and wants the Thunderdrum fledglings away from Berk.