- —Lady Spider[src]
May Reilly's father kept numerous animals in his study, one of them was a spider. One day, May opened the spider's cage so it could get comfort, as she believed it to be upset for its captivity. May then tried to pet the spider, and as soon as her hand got near, the spider bit her. According to May, the spider taught her an important lesson, not to let anyone cage you.
After her father died, May used spare parts of his garage to create a suit with four mechanical arms which enabled her to climb walls. She also created mechanical Web-Shooters.
During a ball May was attending, Electro took the mayor hostage. May used this as an opportunity to debut as the Lady Spider. She confronted Electro, and webbed him up; however, soon the rest of the Six Men of Sinestry arrived. After taking some plans the mayor had hidden in his tuxedo, the six villains were forced to retreat due to the opposition Lady Spider posed to them. Believing she would miss the ball, May left the scene to return there.
During the Totem War, between the Spider-Totems and the Inheritors, May was recruited into the Superior Spider-Army. Soon after, May's group joined the Spider-Army. and they are attacked by the Inheritors, but they manage to escape to Earth-13 excluding May, Miguel O'Hara and Peter Parker who decide to autopsy the body of Daemos, a defeated enemy, to find weaknesses in his species.
The trio manage to trap Daemos who followed them in a cloned body and carry out studies on his old body, even though Peter is killed.  When they then go to the safe zone, May and Miguel discover that many of their comrades have been killed.
Seen Leopardon, the two decide to repair it and to do so they go to May's world. . Discovered the weakness of their enemies to radioactivity they decide to use that to enhance the robot.. Shortly after they are contacted by the leader of their army and after learning of the relocation of their companions, they promise to join them when the work is finished . After a confrontation with the Six Men of Sinestry , the two obtain the radioactive material they need and rejoin the rest of the army during the attack on the world of their enemies. May survives the battle and after the defeat of the Inherithors returns to her world. 
- 4-armed spider-harness
- May was the only female student present during her university schooling.
- 20 appearance(s) of Maybelle Reilly (Earth-803)
- 4 minor appearance(s) of Maybelle Reilly (Earth-803)
- 1 mention(s) in handbook(s) of Maybelle Reilly (Earth-803)
- 31 image(s) of Maybelle Reilly (Earth-803)
- 4 quotation(s) by or about Maybelle Reilly (Earth-803)
- 1 item(s) used/owned by Maybelle Reilly (Earth-803)