It's an age-old conundrum: how to safely store your poisons without accidentally drinking them? You might argue that labels, child-resistant packaging and proper storage provide the answer, but Philadelphia's Dr. William M Caterson had a different idea.
Back in 1875, Caterson filed a patent for a safety container in which the bottle itself is shaped like a skull. This way, according the patent, "it will always act as a caution, for it will be the first thing noticed by day or artificial light, and will be at once detected by the touch in the dark."
You'll actually find some beautiful antique poison bottles, some even shaped like a skull. So I suppose the design took off. Of course, then Dan Aykroyd came along in the 21st century and sold vodka-filled glass skulls to the tune of $55 million, throwing everyone for a curve.