I read that he used to drive around and when he saw a skateboarder, he'd yell "do an ollie" and then give them a new helmet.
https://m.youtube.com/watch?v=ob0dI05Xz8s
Koston did not invent the thing but has been a major popularity contributor to it.
https://www.surfertoday.com/skateboarding/why-do-skateboarde...