In 1975, advertising executive Gary Dahl came up with the idea to sell rocks as pets. Of course, rocks had been used for millennia in construction, engineering, landscaping, even war—but, until then, nobody had thought of a stone as a personal companion.
For those who have developed fruitful relationships with loose fragments of the Earth's crust, there's the Kingii Wearable flotation device.
Weighing in at 4.9 ounces, fitting snugly on the wearer's wrist and named after the frilled-neck lizard, this device is not rated to save people's lives. But, during an aquatic emergency, pull a lever on one of the device's two cylinders to release a bright red, self-inflating balloon that, with the aid of a life jacket and gravity, could help prevent the wearer from drowning.
At $90, the Kingii—like the Pet Rock—is for peace of mind.