black flag Jolly Roger Pirate Flag pirates Skull and Crossbones flag grass icon kranium pirate pole scull tape black boat bones death flagpole sail skull swim appearance danger Flags jolly-roger pirate-flag sign skull-and-crossed-bones symbol symbolic traditional warning bank banking mate privateer sailing ship shipping white beware crossbones dangerous dead death's halloween hazardous head adventure ancient bone buccaneer captain death at sea fear fighting hat horror jolly killing knife murder piracy pirate ship pirates of the caribbean plunder raise the colors robbery rodger sailor sea seafaring skeletal skeleton swashbuckler sword terror vintage voyage walk the plank war watery grave zombie zombie pirate aged antique backdrop background creepy cross crossbone evil free gray grey grime grimy grunge grunged grungy image old omen ominous page paper photo photograph picture resource retro roger scary sheet somadjinn stock texture textured warn