Cooper Baltzell bonded with Gregory Watson during walks to the hospital popcorn machine.

MINNEAPOLIS — Some little boys model superheroes. Cooper Baltzell prefers a real-life hero.

Four-year-old Cooper pushes a toy mop while imitating Gregory Watson, the janitor who cleaned his room at University of Minnesota Masonic Children’s Hospital.

“He’s told me that he’s Gregory,” said Ashley Baltzell, Cooper’s mom. “And our floors are very clean right now.”

Cooper met Gregory about a year ago, while Cooper was a patient at the hospital and Gregory was newly assigned to clean the fifth floor.

The janitor was instantly taken with Cooper.

“I cleaned his room every day,” Gregory said. “He’s always happy.”

Yet, Cooper had every right to be sad.

Born with Hirschsprung's disease - a genetic condition affecting Cooper’s digestive system - he’s been in and out of the hospital his entire life.

Last year, Gregory invited Cooper to join him on a walk to the hospital popcorn machine. The pair has been tighter than salt and butter ever since.

“For his potty chart - for like five stickers and then you get a prize - one time he said he wanted his prize to be to go to the hospital,” Cooper’s mother said.

For Cooper, going to the hospital means more time with Gregory. “He was my best friend,” Cooper said.

On a recent afternoon, Cooper and Gregory talked sports and birthdays while snacking on popcorn in the hospital library.

“I can’t eat no more,” Gregory told Cooper after wadding up in a ball his empty popcorn bag.

“You have to eat some more,” Cooper insisted, while Gregory chuckled at his young friend’s admonition.

Happy that Cooper is now out of the hospital, Gregory hopes the return visits - just for fun - never end.

“He’s just in my heart,” Gregory said.