When "Ultimate Spider-Man" arrives in her dimension, he is surprised to find a female version of J. Jonah Jameson named Joanna Jameson, who like Jonah, slanders superheroes. Spidey encounters Spider-Girl, who is rather angry that there is seemingly a fan boy masquerading as her, constantly telling Peter to stay out of her way, telling him "a boy can't be Spider-Girl". Peter attempts to warn her of the Green Goblin, who is after her blood but Petra still doesn't buy it until Peter uses a familiar quote someone once told him "With great power, comes great responsibility". She finally relents, having heard the quote herself and asked if he was really another version of her from a parallel world, which he confirms. He unmasks himself and introduces himself as she unmasks and introduces herself. After moving past an awkward moment of being put off by their similar appearance, Peter tells her about his Goblin and she having faced a "Goblin" before, thinks she may know his location.
As they arrive at Oscorp, Spider-Man is surprised to see a female version of Green Goblin, named Norma Osborn (voiced by Wendie Malick), who is based on the original incarnation, with a costume, bat-glider, and pumpkin bombs, while Spider-Girl is surprised to see a male Green Goblin (voiced by Steven Weber, based on the Ultimate incarnation, who is monstrous and mutated, yet still uses a glider and bombs. She is shocked at his face and questions if "Goblin is a man or monster", which Goblin replies "Why can't I be both?". As Spider-Girl fights Green Goblin, while Spider-Man fights She-Goblin. After finding an opening to steal a sample of Spider-Girl's blood, and after doing so, Norma asks Norman to give her what she asked for, which is a vial of the Goblin serum. After drinking it, Norma transforms into a monstrous version of herself, fully becoming She-Goblin. As they battle and defeat her, Spider-Girl runs out of web-fluid and falls off of the Georgia Washington Bridge, but Peter saves her. Having defeated Norma, Petra thanks Peter for helping her, saying "it's good to know there's another hero out there, even if he's a boy." Spider-Man return the feeling and bids Spider-Girl farewell as he pursues Goblin.
Spider-Girl returns in "Spider-Verse" Part 4, having been summoned by the "Ultimate" Spider-Man, alongside Spider-Man 2099, Spyder-Knight, Spider-Man Noir, Spider-Ham, and Ultimate Spider-Man, forming the Web-Warriors, in order to combat Goblin, who has injected himself with a serum of their DNA, and has transformed into Spider-Goblin. After defeating Spider-Goblin, Electro, who Goblin had been using as a slave throughout the story, is freed from the Siege Perilous, and having been empowered by it, merges with the Helicarrier, transforming into a massive battle mecha. She motivates the main universe Spiderman to fight by mentioning he helped them do so in their worlds and he gets his strength back. As they fight Electro, he sets the Helicarrier to self-destruct. After Spider-Man defeats Electro, Spider-Girl, with help from Spider-Ham, set the Helicarrier to fly out of reach, where it can detonate safely. With the battle won, Spider-Girl bids her counterparts goodbye, as along with all of the Spider-Men, returns to her dimension.
She makes a cameo in Return to Spidervese part 4, where it is revealed she was attacked by the evil spiderman Wolf Spider and having her life force drain. When Ultimate Spiderman was drained, he entered the world where the other spideys were having their essence drained. However, Ultimate Spiderman motivated them to fight and they were able to overcome their evil counterpart who destroyed himself. After being freed, they questioned Ultimate Spiderman who explained since they were all heroes then their evil self couldn't handle it. Thanking, Spider-girl and counterparts returned home.
- In the comics, the original Spider-Girl was Mayday "May" Parker, the teenage daughter of Peter Parker and Mary Jane Watson, hailing from the MC2, an alternate future of the Marvel Universe. The second Spider-Girl was Anya Corazon, once known as Araña, a member of the Spider-Society.
- In the original Ultimate Marvel comics, Spider-Girl was female clone of Spider-Man, named Jessica Drew (after the original Spider-Woman). This was the first instance of a gender-swapped Peter Parker.
- Two other female versions of Peter Parker, known as Patricia Parker and Peni Parker, appear in the Spider-Verse storyline in the comics. While Patricia was mostly like Petra (a simple student and hero), Peni was the daughter of a hero known as the SP//DR, a battle-armor powered by a radioactive spider.