Squirrel Girl co-creator Will Murray is hazy on when he first uttered the name of his most famous creation, but he thinks it happened at a church in Quincy, Massachusetts, back in 1988.

He was sitting with a friend, Doreen Greeley, when a squirrel popped out of her jacket.

"In the middle of the service, another baby squirrel poked its nose out of her jacket," he remembered in a recent conversation with SYFY WIRE. "She had rescued it. I had no idea it was there. The nickname 'Squirrel Girl' may or may not have originated at that time."

Around the same time, the furry little rodents were pervasive in his life. Murray's attic had been overrun with squirrels and he had become fascinated by the creatures. A few months later, he even rescued a squirrel when it fell out of a tree in his yard. Worried about the animal, he brought it to his friend Doreen.

"She was always into wildlife — she had dogs, cats, ducks, geese, and other critters," Murray recalls. "Somehow, all of this combined in my mind in ways now half-forgotten to produce Doreen Green, aka Squirrel Girl."

Credit: Marvel Comics

Greeley was a freshman at the University of Massachusetts in Boston when she first ran into Murray in 1977. Murray had graduated from UMass Boston a few years back and was freelancing, writing and editing pulp stories like Doc Savage. After a family member fell ill, he returned to his alma mater to work as an English tutor and teaching assistant in several classes.

"I happened to sit next to Doreen in one class," Murray said. "I think she was doodling superheroes and I struck up a conversation about comics. I remember bringing in some copies of the old Comics Buyer's Guide for her to read. I was engaged at the time and recall thinking that if I weren't otherwise in a relationship, Doreen might be the girl for me. We certainly had common interests."

Greeley, a longtime comic book fan, first got her start reading Looney Tunes and Scooby Doo before getting into the "hard stuff." When she was 14, a friend invited her over to look through his comic collection. She marveled at his collection of Silver Surfer, Fantastic Four, and Spider-Man.

"The whole comic world was just a lot bigger than I had thought," she told SYFY WIRE. "I started collecting Wonder Woman, Detective Comics, Daredevil, and Hulk."

According to Greeley, she and Murray "hit it off immediately" and a few years later they were dating. Greeley said the two shared a love for comics like The Shadow and The Spirit, radio plays and pulp books like Doc Savage. "He showed me lots of bookstores and I would often take the train up from Hingham. We went to a lot of movies and even saw an advanced screening of Raiders of the Lost Ark," she said. "It was a big romance but like any relationship, it had its ups and downs."

Over the next year, the relationship sputtered and fell into an on-again, off-again romance. Greeley transferred to Bridgewater State College, over an hour away, but the two remained friendly. They'd often arrange trips to New England Comics precursor New England Collectibles where they'd spend hours browsing and talking over comic books.

Over the next several years, Murray became busier, taking on the Destroyer books and short stories at Marvel, and Greeley finished college. After graduating, Greeley worked for her father before landing a job with the New England Wildlife Center in the late '80s. Still the pair remained in contact, talking comics and spending time on the Greeley family boat, "The Gusty Puff."

Credit: Doreen Greeley

At the New England Wildlife Center, Greeley found her second calling outside of comic books: animals, and in particular, squirrels.

"I was hired for my computer expertise," she said. "But, I soon got into the routine helping out the staff from February to April feeding the influx of baby squirrels."

Well-meaning people, like Murray, would bring baby squirrels they'd saved from all kinds of troubles, she said. Greeley would train them to climb trees and eat acorns, acclimate them to the world and set them free. When Greeley described the work, she lit up with excitement.

"You get to see them grow from the size of a pinky, then they get that big furry tail and they're so fluffy," she laughed. "There was one I really got attached to. Most squirrels were out in a week or two but this one had been bitten or something. She had a crescent scar over her eye and she went everywhere with me from April to November of 1989."

Around the same time, Murray was tinkering with the idea of Squirrel Girl. His career was starting to pick up thanks to a steady writing gig for the Destroyer paperback series. When Marvel acquired the license to the Destroyer, Murray was approached to script the comic book in 1988 for the comic book giant. Soon, he was tapped for a small story in a fill-in issue of Iron Man late in 1989.

"My first goal with Squirrel Girl was to evoke the early fun spirit of Marvel Comics that I enjoyed as a reader circa 1962-64. I thought Marvel had turned too dark by the late '80s. Secondly, I consciously wanted to create a breakout character," he admitted.

Murray finished the filler script "The Coming of… Squirrel Girl," but no emergency arose, so the story was subsequently dumped into Marvel Super-Heroes. Originally, Murray was teamed up with an artist named Tom Morgan and he wrote the script with Morgan in mind.

"When Morgan bowed out, I requested Steve Ditko. I was delighted when he accepted. Steve worked from a full script, yet somehow got a plotting credit by accident," he said. "He designed the costume and came up with the knuckle spike and overall look. I remember suggesting a costume like that of Peter Pan –- which was a clue to Doreen's inner nature. Ditko went to his own way on that. I might add that he was no fan of the character."

A few weeks after working on the character, Murray met Greeley at New England Comics in Quincy to deliver the news.

"He had this impish look on his face and he said you know 'I made you a character, Squirrel Girl,'" Greeley said. "I didn't believe him but he showed me a Ditko sketch of just the head, with the weird makeup and buck teeth. Stil,l I wasn't convinced — I thought he was joking."

Murray didn't stay for long, and when he left, he told Greeley to look for the character in the pages of West Coast Avengers. Greeley started buying the series but she soon fell off and never found that issue. Instead, the story was used in Marvel Super-Heroes vol. 2, #8, a.k.a. Marvel Super-Heroes Winter Special in 1990.

Credit: Marvel Comics

Greeley never saw the book and figured Murray was simply playing a trick on her. It would take Greeley almost 25 years to realize he wasn't joking.

In the early '90s, Greeley left the Wildlife Center and started working at New England Comics. A regular customer there since its opening, Greeley said she took to the job immediately. Towards the end of 2014, Greeley started hearing buzz from customers about a Squirrel Girl solo comic book, The Unbeatable Squirrel Girl.

"Customers started talking about the book but it still wasn't real at that point," she said. "When the book finally arrived it took a while to settle in. My first thought was wow, Marvel must be running out of options, but I loved it. It was fun and it came at a time when Marvel storylines were dark and depressing. Squirrel Girl was such a bright light of humor, excitement and joy."

At the store and beyond, the word started to spread that Greeley might be the inspiration behind the character. Newscasters reached out and Greeley fielded a few interviews but she shied away from the spotlight. For the most part, fans of the book would come in to the shop and buy issues of Squirrel Girl and ask for her autograph.

Greeley said the furor over the character lasted about six months. Around that time, Murray had been tapped to write an issue of Unbeatable Squirrel Girl and Greeley organized a signing in Quincy to mark the occasion.

"It was great to see all of the young fans react so positively to this character," she said.

Fans gave Greeley Squirrel Girl T-shirts and asked her questions about her character. She posed for pictures and signed autographs. One fan, after meeting her, assured Greeley that she would keep her secret identity safe.

"I think it's very important that young girls have a role model to look up to," Greeley said. "Mine was Wonder Woman. Squirrel Girl is kind of a modern take on that. She's lawful, polite and knows how to deal with tough situations."

Video of Watch Squirrel Girl Sketched By Erica Henderson | SYFY WIRE

To Murray, Squirrel Girl's unique popularity stems from her "unswervingly optimistic personality."

The past few years have been big for Squirrel Girl, arguably Marvel's most positive, plucky and powerful character. She's starring in the upcoming Marvel Comics' Secret Warriors cartoon alongside a new generation of heroes including Spider-Gwen, Ms. Marvel and America Chavez and her solo book, The Unbeatable Squirrel Girl has enjoyed years of success since its 2015 launch.

"While Squirrel Girl has grown up and her personality has matured — and even mutated –– the surviving essence of the character is pretty much what I had imbued into her. Squirrel Girl possess a lot a heart, and I'm pleased to say that the creators who followed me have continued in that vein," he said. "Doreen has grown in ways I would never have imagined and evolved into a inspiration figure for 20th Century girls and women. Maybe she was ahead of her time and the 21st Century needed her more than the 20th ever could."