Some call her the Squirrel Whisperer. Others go with Squirrel Girl. Either name suits Mary Krupa just fine.

Four years ago, Krupa became an internet sensation. As a freshman at Penn State University, she made some unusual friends: the abundant campus squirrels.

As a freshman in 2012, Krupa wondered what a squirrel would look like with a tiny hat on its head. She managed to get one on and snapped a picture.

Soon Krupa was holding photo shoots: plopping little caps, bonnets, or boaters—once even a helmet—onto furry noggins. She’d often coax squirrels to hold miniature props—a “Go Penn State” sign or a basket of Easter eggs.

Photos of “Sneezy the Penn State Squirrel” garner thousands of likes on Facebook. They’ve been featured in magazines and calendars.

Krupa kept dreaming up amusing scenes for her squirrelly star: Sneezy pushing a tiny shopping cart filled with acorns, playing football, raking leaves, teaching school, having a tea party. Most of the photos feature Sneezy in a squirrel-sized hat.

“It’s nice to make something and see that people like it. But I didn’t think it would last this long or become this popular,” Krupa admits.

Squirrel Girl is an unlikely celebrity. Growing up, she was always fond of wildlife. People were another matter.

Diagnosed with Asperger’s syndrome, a mild form of autism, Krupa was a loner in high school. But at college, Sneezy helped her feel less awkward.

“The squirrel’s actually a good way to break the ice. I’ll be sitting here patting a squirrel, and other people will come over, and we’ll just start like feeding the squirrels together and chatting about them,” she says.

Though she’s graduated from Penn State, Krupa still plays with the campus squirrels. She lives in the area—ready to welcome the next class of Penn State squirrels.

One afternoon, Krupa looked for Sneezy near the trees alongside Penn State’s Old Main. She called softly, holding a container of peanuts under one arm.

A few minutes later, a squirrel sat on Krupa’s lap. It’s the current Sneezy. (There have been several.) Krupa stroked the squirrel, and then placed her favorite hat—a fruity creation made with a 3-D printer—atop Sneezy’s head. It fell off, and the squirrel scampered away.

“They’re definitely wild animals, and I always respect them,” says Krupa, who minored in wildlife science. “But at the same time, it’s neat that they’re willing to let me interact with them. We do seem to have this mutual trust.”