Rachel Chase, a longtime New Yorker, is used to seeing rats in Central Park. Rats rattling the bushes. Rats scurrying across sidewalks. Rats lurking just behind fences, their little black eyes alert.

But last Saturday, the rats of Central Park were like nothing she’d ever seen.

At midmorning she took her children, ages 2 and 4, to the Wild West Playground, near the park’s entrance at West 93rd Street. It’s an awesome spot, with forts, sandboxes and slides.

At around 11:30, Ms. Chase started readying to leave. She needed to be at the Ambassador Theater an hour before curtain for the 2:30 matinee of “Chicago the Musical.” (She stars in the show, playing Roxie Hart.)

Then, as she was about to grab her stroller, she saw movement. It was in the undercarriage, down where Ms. Chase keeps toys, baby wipes and sippy cups. She yelled, “Hey!”

Two rats — possibly three? — climbed out of the stroller and bolted away.

Aware that her children were watching, Ms. Chase did not freak out. Instead she calmly cleaned the stroller seat with antibacterial wipes, helped her children inside and then walked home, where she attacked the stroller with different combinations of dish soap and bleach.

“I wanted to set it on fire,” she said of the rat-defiled stroller. “It’s just gross. It’s so gross!”