The Sheep Launcher was a type of catapult designed to fire sheep into the air during the dragon races.
Sometime within three years after the end of the Berserker war, the Dragon Riders started a tradition of Dragon Racing. Snotlout Jorgenson built the launcher for the dragon races. It took Snotlout 32 tries to perfect the launcher.By the time of the events of the second movie, Gobber had given the launcher wheels for great mobility. Gobber then uses it during the dragon race to fire the black sheep. It is used again toward the end of the movie as a way of distracting Drago's bewilderbeast so Hiccup could get Toothless back. Following Drago's defeat, Gobber continue to use the launcher for the dragon races.