Misaka 50020 (ミサカ五〇〇二〇号 Misaka Goman Nijū-gō?), also known as Pet Misaka (お手ミサカ?), is a non-canon Sister, a clone of Misaka Mikoto, who appears in the Toaru Majutsu no Index parody story, Konna Saishuu Banashi wa Iyada!!.
Like the other Sisters, Misaka 50020 looks the same as Misaka Mikoto, though her eyes are drawn differently for emphasis. Like all Sisters, Misaka 50020 wears Tokiwadai Middle School's uniform and blue-striped panties, but instead of wearing goggles, she has dog ears.
Konna Saishuu Banashi wa Iyada!!
- Main article: Konna Saishuu Banashi wa Iyada!!
Misaka 50020 is with Kamijou Touya when Touma encounters him, having been picked up by him earlier. When Touma asks if she is an Abandoned Misaka as well, she introduces herself by serial number, declaring that she is no longer an Abandoned Misaka and has begun her second life as Pet Misaka. She and Misaka 20002 are left behind when Touma and Touya run into a burning building to save Itsuwa. Though not thinking too much of it at first, they both look back towards the building after Kamijou Shiina points out what might happen with the two of them rushing in to save a girl.