Nathaniel Wellen, a 15-year-old high-school freshman, sold his idea for an umbrella for two on the ABC show.
The patented Duo umbrella offers a second drop-down handle so that two people can hold on at the same time.
Nathaniel came up with the idea when he was seven years old and got soaked while walking to school with his dad.
"Whoever had the umbrella the other person got wet and it was not a great experience," Nathaniel recalled. "And I thought what if there was a second umbrella handle for me to hold onto?"
Father and son worked out the concept together, going through one prototype after another in the family garage.
"It was so cute because a lot of fathers and sons play football together and go fishing together and they did do that too but they innovate together," said Nathaniel's mother Kris. "They would be in the garage breaking umbrella after umbrella."
Alex Wellen got his son a patent for his 10th birthday. He later won a prize at the Invention Convention and by 2022 they got together with the weather accessories brand ShedRain, which owns 49% of the company.
Now a famous shark owns a piece as well.
Nathaniel went into his pitch asking for $100,000 for 10% of the company. He eventually struck a deal with Robert Herjavec for 18% at $100,000.