|Master||Oikawa Yukio / Vamdemon|
|Voice Actor||Morikawa Toshiyuki (森川 智之)|
Mummymon is a hybrid composed of data and human DNA, created by Oikawa Yukio. As a hybrid, he is capable of transforming from his Digimon form into a more humanoid form, albeit with an odd physique; he has grey skin, one golden eye and a wide mouth full of sharp, shark-like teeth, as well as wide shoulders and long hands and forearms.
Though he is an enemy of the Chosen Children, Mummymon isn't very villainous, and is in fact rather cheerful and friendly. He is often a bit reluctant to fight, but he is blindly loyal to Oikawa and to Archnemon, his partner and fellow hybrid, and will do anything they want him to do. He is deeply in love with Archnemon, though she constantly rejects him. However, he is an optimistic fellow, and keeps hoping she will return his affections.
He first appeared in "Archnemon, the Spider Woman's Mistake", coming to rescue an injured Archnemon when she was on the verge of defeat. Though she was glad to see him, she later berated him for not killing the Chosen Children when he had the chance. Following this, the two were rarely seen apart.
It was Mummymon that suggested to Archnemon that they should go and destroy the Holy Stones that were rumored to keep the Digital World's balance in check. While they found the first Holy Stone difficult to destroy, a Knightmon Archnemon had created from a Dark Tower managed to delete the Holy Ring surrounding the stone, which prompted Black War Greymon to destroy the stone. Pleased with the turn of events, Archnemon and Mummymon follows Black War Greymon around as he searched for the Holy Stones, fighting the Chosen Children off to prevent them from stopping the destruction of the Stones. However, when only one Holy Stone was left, the Chosen Children used their Digivices to free Qinglongmon and the Holy Beasts from their imprisonment inside the Stones, and they used their power to reseed the Stones, foiling Archnemon and Mummymon's plan.
Following this, Oikawa decided to adopt a more direct approach. On Christmas, after spreading Dark Towers and opening Digital Gates all over the Real World, he sent Archnemon and Mummymon in a truck to kidnap twenty children from around Tokyo. The next day, they kidnapped Ichijouji Ken as well, and Oikawa scanned Ken's Dark Seed and spread it to the other children. They drove all the way to Hikarigaoka, where Demon stopped the truck, demanding to have Ken. As the Chosen Children fought Demon, Oikawa, Archnemon and Mummymon escaped, not before Oikawa told the Dark Seed children to come back to Hikarigaoka on December 31st. The three hid away in a vacation house in the mountains, but Black War Greymon found them there, intending to kill Oikawa. He revealed to them that he had sensed Archnemon and Mummymon weren't fully Digimon, and that there was something not human in Oikawa as well. However, after receiving unexpected help from the Chosen Children, they escaped back to Tokyo.
Following the revelation that they were created using Oikawa's DNA, a troubled Mummymon tried to speak to Archnemon about their origin, but she refused, telling him that they should focus on their mission.
On December 31st, the seeded children were rounded up on the bridge in Hikarigaoka, and Oikawa used their power to open a gate to another world. However, it wasn't the Digital World, but rather a world of dreams. Vamdemon, who had possessed Oikawa and dictated his actions, revealed himself and came out of Oikawa's body to absorb the rest of the children's Dark Seeds. As he became the terrifying Belial Vamdemon, he grabbed Archnemon, tortured and killed her. Mummymon was stricken with grief, and in his rage, he mindlessly attacked Belial Vamdemon. However, he wasn't strong enough, and Belial Vamdemon killed him as well using his Melting Blood attack.