Gary Dahl joked about a pet rock in a bar — then sold 1.5 million of them at $4 each

In 1975, advertising executive Gary Dahl was in a bar with friends, listening to them complain about their pets — the feeding, the walking, the vet bills, the mess. He joked that a rock would be the perfect pet: no feeding, no walking, no grooming, no vet bills, and it would never die or be disobedient. The joke got laughs, and Dahl kept thinking about it.

Dahl wrote a humorous instruction manual for a 'pet rock,' covering topics like 'How to Make Your Rock Roll Over' and 'How to Housebreak Your Rock.' He recruited two colleagues, George Coakley and John Heagerty, as investors. They bought smooth gray stones from a Mexican beach for less than a penny each, packed them in a cardboard box with straw and breathing holes, and included the manual. The Pet Rock was sold for $3.95.

Dahl debuted the Pet Rock at the San Francisco gift show in August 1975. He was swarmed by retailer orders. By Christmas 1975, the Pet Rock was the hottest gift in America. Dahl sold nearly 1.5 million units in six months, turning a 95-cent profit on each one. He became a millionaire overnight. The product was a joke that had become a phenomenon.

The fad lasted about six months. By February 1976, sales had collapsed. The Pet Rock became a textbook example of a fad product — a novelty that burned hot and died fast. But Dahl had already made his fortune. The rock that was never meant to be a product had sold more than most serious inventions.