The Big Drums appear to be large drums whose sound can carry a very long distance to summon Vikings together. In the case seen in How to Train Your Dragon, Stoick the Vast used them to gather the Hairy Hooligan Tribe and the Meathead Tribe for a Council of War. Mogadon is skeptical about why Stoick used the Big Drums, as there wasn't any apparent "ghastly deadly peril". However, the peril was the appearance of the colossal Green Death on Long Beach. Mogadon remains skeptical until he sees the Dragon for himself.