Doreen Green (Earth-616)
Doreen Green, alias Squirrel Girl was born a mutant with squirrell like attributes. With her new powers she wished to be a usperhero. She ambushed Iron Man in a forest and hoped to impress the veteran hero, wishing him to take her under his wing as hissidekick.
Unimpressed, Iron Man politely declined, when suddenly the duo was attacked by Doctor Doom in a large aircraft. Doom captured and subdued Iron Man, and began to fly out over the ocean where he planned to dispose of Iron Man's body once he killed him. Underestimating her, Doom left Squirrel Girl to her own devices. She devised a plan, and used her ability to communicate with squirrels through an open door as the ship passed over the forest. Hundreds of squirrels answered her call and flooded Doom's ship, chewing through the wires, and swamping the evil dictator with their furry bodies. Doom exclaimed "Confound these wretched rodents! For every one I fling away, a dozen more vex me!" Iron Man was freed, they emerged victorious, and the two heroes went their separate ways.
She relocated to New York City. While fighting crime in Central Park, she saved the GLA from muggers who then recruited her. Alongside her new teammates Squirrel Girl witnessed the death ofGrasshopper and became very frightened but was determined not to give up. Thanks to her "squirrel army", Squirrel Girl was able to help stop Maelstrom from destroying the world.
Added by K higgins563
After Squirrel Girl made a fuss to be certain that Monkey Joe was an official member of the team, he was apparently killed by Dr. Doom seeking revenge. In actuality, this was a rejected member of the GLA named Leather Boy in a variation of Dr. Doom's costume. Squirrel Girl found a new squirrel companion in the next issue, the only one of her "squirrel army" who had survived Maelstrom's wrath, whom she named Tippy-Toe.
Squirrel Girl and Tippy Toe managed to defeat M.O.D.O.K., Terrax, and Thanos all by themselves. Uatu, the Earth's Watcher, was on hand to confirm that the Thanos she defeated was the real thing, and not a clone or copy of any kind. After M.O.D.O.K. was defeated,Dum-Dum Dugan offered her a position at S.H.I.E.L.D., explaining that they'd been watching her for some time and found her to be one of the most effective people ever at defeating powerful super villains. Squirrel Girl declined the offer, saying she was happy being with the GLA. Squirrel Girl was one of the lucky 198 to retain their powers afterM-Day.
She later helped the thing defeat Bi-Beast. While visiting squirrel friends in Central Park, Squirrel Girl came across Thing fighting with Bi-Beast. She told the squirrels to retrieve the smelliest garbage they could find and place it around the combatants, resulting in everyone having to hold their noses. Bi-Beast had to use both hands to hold his noses, leaving himself defenseless, allowing Thing to knock him out.
Squirrel Girl and the rest of the newly-renamed Great Lakes Champions, who took the name after winning a poker game, registered under the Superhero Registration Act the morning the law was enacted. However, mercenary-for-hire Deadpool, assuming the Champions were un-registered, attacked the team at their headquarters (Deadpool sought to ingratiate himself with the government by capturing un-registered heroes). Deadpool was bested in combat by Squirrel Girl; his distraction at her appearance and name contributed to his inability to mount an adequate defense to her attacks.
Squirrel Girl and the again-renamed Great Lakes Initiative teamed up with Deadpool a few months later to take down AIM agents who had kidnapped a wayward Olympian God and fashioned an inebriation ray that made every superhero on the planet (save for Deadpool and the GLI) drunk. After the battle, Deadpool decided to hang around the GLI's new government-funded headquarters for a while as a "reserve member."
Squirrel Girl was a huge fan of the New Warriors, especially Robbie "Speedball" Baldwin, on whom she had a crush. She learned of Speedball's transformation into the darker hero code-named Penance after Deadpool provided her with a copy of Civil War: Front Line #10. Squirrel Girl traveled to Thunderbolts Mountain to convince Robbie to lighten up and stop being Penance. Frustrated by his current attitude and unwavering determination to remain as Penance, Squirrel Girl traveled to Latveria to use one of Dr. Doom's time machines to travel to the past and prevent Speedball from ever becoming Penance. The machine instead transported her into the future, where she encountered an alternate version of Speedball (whom she unsuccessfully tried to get to travel back to the past with her), and Mr. Immortal, who told her she has an important task to perform in the past — namely, kicking Deadpool out of the Great Lakes Initiative's headquarters.