Lonnie George Johnson (born October 6, 1949) is an American inventor, aerospace engineer, and entrepreneur, whose work includes a U.S. Air Force-term of service and a twelve-year stint at NASA, where he worked at the Jet Propulsion Laboratory. He invented the Super Soaker water gun in 1989, which has been among the world's bestselling toys ever since.

The Super Soaker was the result of an accident. Johnson was at home in 1982 working on an idea for an improved heat pump – a device for heating and cooling that mechanically transfers heat to another source – when his creation sprang a leak. A burst of water shot across the room and Johnson immediately thought, “That would make a great squirt gun.”

He worked on the concept and made a prototype from Plexiglas, PVC pipe, O-ring seats and other handy materials, including a two-liter soda bottle for the ample reservoir. Whatever parts he needed but couldn’t beg, borrow or steal, he made on a small lathe in his workshop at home.

The original prototype, which Johnson still has, was a far cry from the squirt gun available on store shelves. The array of white PVC pipes and bulbous reservoir gave it a Star-Wars-ray-gun look. But as jury-rigged as it looked, the prototype could shoot: a compressed blast of water could carry up to nearly 40 feet.

In 1986, Johnson received U.S. Patent 4,591,071 for a device simply titled “Squirt Gun.” Johnson struggled for several years to find a company that could turn his idea into a commercial success. There were many skeptical responses and several false starts until finally in 1989 one toy manufacturer realized the potential for his drenching device. He licensed it to the Larami Corporation, which initially marketed the toy as the Power Drencher in 1990.

It took some tweaking and rebranding until the toy took off. It was relaunched as the Super Soaker. At a retail price of $10 each, sales soared to $200 million, catapulting it to the top-selling toy in the world in 1992. It has been one of the top-10 toys sold every year since then.

According to smithsonianmag.com & Wikipedia