Murray created the character out of a desire to write lighthearted stories, in contrast to the heavily dramatic tales that were then the norm in mainstream comics.

Doreen has also appeared in her own solo series, which have depicted her dividing her time between her superhero adventures and her work as a college student.

After Squirrel Girl made a fuss to ensure that Monkey Joe would be an official member of the team, he was killed in the third issue.

Slott's stories satirized Squirrel Girl's unlikely victory over Doctor Doom from her debut appearance by depicting her as capable of defeating some of Marvel's other highest-ranking supervillains, including MODOK, the Mandarin, and Thanos, mostly in comedically unexplained, off-panel ways.

Strong trade sales at school book fairs encouraged the team to develop an original graphic novel, The Unbeatable Squirrel Girl Beats Up The Marvel Universe!, released in October 2016.

It is written by North, directed by Giovanna Sardelli and stars Milana Vayntrub as Squirrel Girl; the series is produced by Radio Point.

When she was 10 years old, Doreen discovered she could communicate with squirrels; she suffered a modification in her genes for unknown reasons that granted her squirrel-like abilities, which manifested predominantly as a prehensile tail.

[19] Squirrel Girl and the GLI, along with Deadpool, are sent to save Dionysus after he fell from Mount Olympus and was captured by A.I.M., who planned to use his powers to cause mental instability in superheroes they consider a threat.

[21] After defeating Fin Fang Foom and finding little support from her teammates on the again renamed Great Lakes Avengers, whom she believes have her shoulder most of their work, she exits the group.

Shortly thereafter, while attempting to stop Hippo from robbing a bank, she meets Chipmunk Hunk and Koi Boi, both of whom have the ability to speak to different animals.

They later encounter a monstrous Asgardian squirrel god, Ratatoskr, who had been causing mayhem on the city by trash-talking its citizens during their sleep, but is defeated with help from Loki and the current and former Thor.

[32] During their second college year, Doreen and Nancy encounter Brain Drain and quickly defeat him due to his outdated technology and crucial design flaws.

He threatens to bury a number of worldwide landmarks if she doesn't date him, and after Nancy is nearly kidnapped by him and being swarmed by the media, she goes to confront Mole Man only to find that the Tricephalous is in love with him.

Doreen lets the beast defeat her to woo Mole Man and get him off her back for good, and decides that dating isn't right for her at the moment after seeing that Mary is a nice fit for Chipmunk Hunk.

[37] She later receives a wealthy benefactor in Melissa Morbeck, a woman who can talk to animals who gives Doreen a new "flying squirrel" suit.

[38] Later stories see Squirrel Girl traveling to the Savage Land[39] and outer space, where she clashes with Loki, Drax the Destroyer, and the Silver Surfer.

[40] After she returns home, a clash with a small-time livestreaming criminal inadvertently sends Doreen and Nancy into hypertime; the two girls quickly age into old women and become close as they find common interests.

They eventually devise a means of reversing time so they revert back into teenagers and forget their lives together, but Doreen finds a note written by her future self to preserve the memory of the brief happiness they shared.

[41] While visiting Allene in the Negative Zone, Squirrel Girl is summoned by Loki to help fight the Frost Giants in the War of the Realms.

[42] Afterwards, Melissa Morbeck returns with an alliance of supervillains (including Doctor Doom, MODOK Superior, Leader, and Whiplash) to enact revenge on Squirrel Girl - kidnapping Brain Drain, stealing Iron Man's armor, attacking Doreen's apartment, and finally publicly leaking her secret identity.

[46] During Squirrel Girl's first encounter with Iron Man, she provided a detailed demonstration of her powers and abilities: a furry, prehensile tail roughly 3–4 feet long, sizable buck teeth strong enough to chew through wood, and superhuman strength and agility that allows her to easily jump between trees.

Later appearances have revealed additional abilities possessed by Squirrel Girl including heightened reflexes (which she dubs her "squirrelgility") and vision (her eyes have been seen to glow red in low-light situations) and she has also at times displayed an enhanced sense of smell.

In the GLX-Mas Special, she is shown flying a small gyrocopter called a "Squirrel-A-Gig" and mentions it was a gift from GLA teammate Big Bertha.

Squirrel Girl is shown as being able to fly the craft expertly, including through the anti-aircraft defenses surrounding Castle Doom, crediting this to her "squirrelgility".

[16] However, the same writer responsible for that story would soon after write another tale in which Thanos claimed to have perfected a means of creating clones of himself that could fool even "the most cosmic of beings."

However, everything that is great about Squirrel Girl was present to some degree from the very start,"[86] while Cameron Bonomolo ranked her 10th in their "Steve Ditko’s 10 Best Marvel Co-Creations" list.

[90] Co-creator Will Murray has expressed interest in returning to the character: "I’ve been thinking of pitching Marvel a Squirrel Girl project.

Thing walks in, stopping the game to reveal that the figurines actually belong to the Puppet Master and are made out of his "Mind Control Clay".

The next day, Squirrel Girl and Pixie read in the Daily Bugle that the clash between the Avengers and X-Men has occurred and have been mirroring the results from their game, implying that they were the cause of the feud.

[95] Squirrel Girl and Jessica Jones are killed by Luke Cage after he succumbs to the Survivor 118, a virus that causes those infected by it to become feral to the point of engaging in cannibalism.