AVALANCHE symbol of skull and bones greatly resembles the pirate flag Jolly Rogers. Although the traditional skull and crossbones pirate flag prevalent in popular culture is usually depicted as black, many historians agree that the original pirate flag was red; red flags were common in naval warfare, to signal that no quarter would be given. This red flag was called Joli Rouge (pretty red) by the French, and may have been corrupted into English as Jolly Roger.