It was a “classic situation” for an inventor, says Lonnie Johnson of the moment in 1989 when he waited nervously for a meeting with toy executives at Larami, a pink Samsonite suitcase on his lap. Inside the suitcase was a new kind of water gun. Instead of a pistol that piddled out a thin stream, this toy was engineered to spray water dozens of feet. “I had bought a milling machine and made all of the parts myself out of PVC pipe and Plexiglas,” Johnson says. “Even the valves — I made those too.”

Johnson had worked on bigger projects. He was a senior systems engineer on the Galileo mission to Jupiter, based at NASA’s Jet Propulsion Lab in Pasadena, Calif. But he still worried about how his invention would go over. As an African-American in a field in which minorities were rare, he was often underestimated, he says. “Most of my career as an engineer, I was put in environments where I was the only person of color in the room.”

Johnson knew that the toy industry could be fickle. “It’s like the entertainment industry. You can’t predict whether a song is going to be a hit and how everyone will react to it.” When he finally stepped into the conference room, Johnson didn’t say much. Instead, he opened up his suitcase and pulled out a water gun, with a cartoonish plastic bulb mounted on top, that looked like a prop from “Plan 9 From Outer Space.”

“Does it work?” Myung Song, the company president, wanted to know. Johnson pumped the gun and pulled the trigger. Water blasted across the room and splatted against the far wall. There was a stunned silence. “Wow,” Song said.