Skull and crossbones

the warning children liked

Unicode: U+2620 skull and crossbones
Meaning: Death — as a memorial, as a threat, and as a hazard label.
History: Three careers that keep interfering with each other: the tomb-carver’s memento mori, the pirate flag, and the poison label. The third failed measurably. In 1971 the Pittsburgh Poison Center found that small children were attracted to the skull rather than warned by it, associating it with pirates and, locally, with a baseball team — and commissioned a scowling green face, Mr. Yuk, to replace it. A symbol tested against its actual audience and found to do the opposite of its job.
Variants: Crossed bones or crossed swords; the GHS uses the skull without bones for acute toxicity.
Related: † Dagger; ☣ ☢ the hazard set; Mr. Yuk in Visual Grammar.
Appears: Poison labelling, high-voltage warnings, pirate flags, military insignia, and gravestones.
Evolution: Funerary art → flag of threat → hazard warning → a case study in symbols that backfire.

Sources · 3

documented The Pittsburgh Poison Center’s development of Mr. Yuk, 1971, following findings on children’s response to the skull.
documented The GHS acute-toxicity pictogram, which retains the skull.
documented The Unicode Standard, U+2620 SKULL AND CROSSBONES.