We’re the Hungarian Horntails! Are you ready to burn this place down into a fiery wreck?” yells 8-year-old Darius Wilkins, onstage with bandmates Rayn Feeney, 9, and his younger brother, Holden, 5. They’re in the middle of sound check on a muggy Saturday afternoon in June at Pete’s Candy Store in Brooklyn. Seconds later, there’s another high-pitched yelp from Darius: “We’re the Hungarian Horntails, and we’re going to blow this place up with fire and rock!”