Meet a 71-year-old who retired as a radiologist and professor, and now runs a banana-skewer business: ‘I never want to retire. Why would you do that?’

At 71, Richard Brown feels as if he’s a college student all over again.

A nuclear medicine physician turned professor, Brown formally retired in 2020—only to take another job in university leadership the following week and join a venture-backed health care startup.

Now, he’s reinventing himself once again, this time as a product entrepreneur —and it has him more excited than ever.

“My hobbies tend to be learning something new,” Brown told Fortune in a recent interview.

“I think I never want to retire,” he added.

“Why would you do that? You spent all this time learning something—and things get easier for you when you get older in some ways because you’re a little bit wiser.” His latest experiment is Poka Snack, a skewer-like product designed to make it easier to freeze and eat fruit, particularly bananas.

Earlier this year, Brown launched it on Kickstarter, where it has raised more than 90% of its initial $4,000 goal, and he’s already amassed more than 14,000 TikTok followers .

But for Brown, the venture is more than a frozen skewer business.

It’s another opportunity to step outside his comfort zone, learn something unfamiliar, and find the energy that comes with starting over .

“It’s almost like being in college again,” Brown said.

“You have that adrenaline flowing.

You want to accomplish something.” Don’t be afraid to ‘look stupid’ and take risks, Brown says Brown graduated from the University of Michigan’s medical school in 1980 and spent the next two decades in private practice.

In 2004, he returned to his alma mater as a professor, while also serving as director of clinical nuclear medicine and molecular imaging in the university’s division of nuclear medicine.

He retired from Michigan in 2020.