In 1975, advertising executive Gary Dahl sat in a bar listening to friends complain about their pets: the feeding, the walks, the vet bills. His deadpan reply was that the perfect pet is a rock. It never dies, never disobeys, and never needs a bath. Most bar jokes end there. Dahl saw a product. He persuaded two colleagues, John Haggerty and George Coakley, to risk their savings, bought ordinary stones from Rosarito Beach in Mexico for a fraction of a penny each, and packed them in cardboard carriers with air holes and a bed of straw.

This episode shows that the stone was never the product. The packaging and a straight-faced 32-page training manual gave buyers a comedy routine to perform for friends, and the Pet Rock spread like viral marketing before the internet. The fad burned out as fast as it rose, but the brand has since found a second life, including a sincere one in South Korea, where overworked people keep the stones for calm and companionship.

• After debuting at a San Francisco gift trade show in August 1975, the Pet Rock sold nearly 1.5 million units by Christmas at just under four dollars each, a 95 percent profit per unit.
• The manual explained how to teach a rock to sit and stay, and noted that rolling over required a little assistance from the owner.
• A 1976 bicentennial edition with an American flag painted on the stone flopped, because decoration spoiled the blank canvas the joke depended on.
• Dahl died in 2015 at age 78. In 2022 the toy company Super Impulse bought the rights, and A24 released a googly-eyed version tied to Everything Everywhere All at Once.
• In the 2020s South Koreans, including K-pop stars, adopted pet rocks in earnest as a tool for venting and meditation, the opposite of the original gag.