The character was created by Tom DeFalco and Ron Frenz as the teenage daughter of Peter Parker (Spider-Man) and Mary Jane Watson, and first appeared in What If #105 (February 1998).

The character made her cinematic debut in the 2023 feature film Spider-Man: Across the Spider-Verse, with an infant Mayday depicted as the daughter of Peter B. Parker and his universe's Mary Jane Watson.

Following positive fan response to the concept, Spider-Girl and two other series (A-Next and J2) set in the same alternate future universe were launched under the MC2 imprint.

She appeared again, handled by the original creative team, in July 2015 as part of Marvel's Secret Wars event, serving as a backup story in Christos Gage's Spider-Island.

In November 2022, a new serialized adventure starring Mayday was launched on the Marvel Unlimited Infinity Comics app, with the story penned by Stephanie Williams.

From the early part of her career onward, Spider-Girl has developed a reputation for avoiding unnecessary battles with anyone and reforming her former adversaries, like Normie Osborn and Raptor.

[volume & issue needed] In The Amazing Spider-Girl, May promises to give up costumed super-heroics, dates Eugene Thompson, and runs for student council.

When Mary Jane becomes aware that the Hobgoblin poses a threat to her goddaughter's teenage friends, she allows May to resume her activities as Spider-Girl (a situation they wanted to keep secret from Peter).

Her success is not without a measure of collateral damage: not only is Moose furious at Spider-Girl for dooming his father, but the sonic weapon renders Ben deaf.

Araña also has an ulterior motive: by assuming the body and power of Spider-Girl she hopes to take the Black Tarantula, an adversary and former lover, by surprise and defeat him.

[13] Bonding with his "daughter" (and, unintentionally, Spider-Girl), the possessed Peter declares himself as "The Goblin God" and begins to go on a rampage, while May finds herself trapped within her father's mental psyche.

With the aid of the spiritual influence of her Great Aunt May Parker, as well as flashbacks to the day she healed Normie Osborn's psychological scars, Mayday and Peter are able to overcome Norman in a psychic duel and convince the Brand New May that May is a good person (but May tries to attack the changeling).

[14] With the Brand New May uncertain of her place, May proposes she become a member of the Parker family; Mary Jane agrees, though Peter distrusts her and objects to the idea.

[14] In the meantime, whilst trying to control the rising gang warfare in New York City as well as keep her unruly cousin in line with both her temper and powers, Mayday's relationship with comic book artist and friend Wesley begins to blossom into a deeper bond, and Wes at times demonstrates hints that he knows May's identity.

April eventually takes on the name "Mayhem" and embraces her symbiotic, intense, no-nonsense nature and cuts herself off from The Parker family to pursue a life as a vigilante who answers to no one.

Two alternate universe Spider-Men consisting of Spider-UK and Last Stand Spider-Man appear in time to save May and Ben as Daemos emerges from the Parker home.

When Peter and Octavius clash and do battle with each other, Mayday requests that Captain Universe Spider-Man intervene and stop the fighting, as better time and energy could be spent tracking down the Inheritors, but the Cosmic Spider refuses.

[20] Following the events of Secret Wars, the MC2 universe, along with most of the multiverse, is destroyed and is merged with several other alternate realities by God Emperor Doom into the patchwork planet called Battleworld.

[15] In the 2018 comics event Spider-Geddon and the spin-off mini-series Spider-Girls, Mayday is once again recruited to help the Web Warriors combat The Inheritors, who had managed to escape their confinement and had set up residence on Earth 616.

Annie learns that she is the pattern weaver, the fourth Spider involved in the prophecy alongside Mayday's brother Benjy (The Scion), Silk (The Bride), and The Other.

No longer dating Wes, Mayday began to flirt with a new student called Jason, and aided both pairs of Lady Hawks thwart a nearby crime.

Mayday's parents offer him breakfast, and it is revealed Peter has returned to active duty as Spider-Man, a fully healthy leg restored to his body, removing his long-standing handicap.

[30] The stillbirth of his child, combined with the death of Ben Reilly at the hands of the Green Goblin that same night, prompts Peter to retake the Spider-Man identity.

During the "Sinister War" arc, it is revealed that Mephisto erased the Parkers' marriage to ensure that their daughter does not exist, as she would one day end his eventual reign over the Earth.

In a time-travel arc taking place in the UK-based publication The Spectacular Spider-Man, aimed at a much younger audience, Peter meets a Spider-Girl whilst trailing the Sandman in the future.

Within those stories he introduced an alternate version of Spider-Girl known as Swiney-Girl (May "Mayday" Porker), who has similar background history with Spider-Girl, with her being the daughter of Peter Porker and Mary Crane Watsow, her father losing his leg after the final battle between Norman Osbird/Green Gobbler, and saving her father as Swiney-Girl from the grandson of the Green Gobbler, Norman Osbird Jr.[38] In this continuity, Peter and Mary Jane have a daughter named Annie May Parker, who eventually becomes the superhero Spiderling.

For the first ten years of their lives, the two were solely raised by Mary Jane in Portland, Oregon after she left Peter following a traumatic incident.

By 2019, Claire has become Spider-Woman (now wearing a costume similar to Ultimate Jessica Drew's), and is instructed by her father to stay behind to protect her brother and mother as he goes to space to end Doctor Doom's reign of terror on the planet with Miles Morales.

[2] An older, more cynical incarnation of Mayday Parker / Spider-Girl appears in the Spider-Man / X-Men crossover novel Time's Arrow 3: The Future by Tom DeFalco and Rosemary Edghill.

This version wears a costume based on that of Jessica Drew's, modified to resemble Spider-Man's, and has the ability to fire venom blasts like Miles Morales.