Skull and crossbones
The skull and crossbones was a symbol for death and, later, for indicating that a thing was poisonous. It consisted of a Human skull and two femur bones. The bones were either placed behind or below the skull. 

On Earth, during World War II, the certain units of the Schutzstaffel, a paramilitary organization based in Nazi Germany, wore the insignia of the death's head (totenkopf), which was a stylized skull and crossbones. () In an alternate 1944, these badges were worn on the left collars of all Nazi SS soldiers fighing in that version of . ()

In 2380, when Badgey created the computer viruses to infect Jackabogs ship, each of the three colored choices was marked by the skull and crossbones. ()

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Symbols