Nightmare of Baldimore

The Nightmare of Baldimore (バルジモアの悪夢) was an incident that occurred when a large portion of the island, Karakuri was blown up by an explosion caused by Franky, who activated the self-destruct switch in Vegapunk's laboratory. Although Kitton's grandfather warned him about it, Franky mistook the button's skull and crossbones design for a pirate symbol and pressed it, causing the whole lab to explode. News of the incident swiftly spread around the world and was dubbed "The Nightmare of Baldimore".

Trivia

 * This is the second time a "danger" skull and crossbones was mistaken for a jolly roger, the first being when Chopper went to look for the poisonous Amiudake mushroom. Interestingly, both instances involved a doctor of one profession or another, and both occurred on Winter Islands.