Uploaded October 2025 | Updated September 2026, 1 week ago
HAPPY HALLOWEEN!!!
Believe it or not, I originally made this AU a year ago and waited to release it until this Halloween! Fell free to ask anything about the AU!
|[Credits]|
Undertale - Toby Fox
Undertale The Insanity Virus - Many Miles Hedgehog/Maxwell Power
|[Lore]|
Before the war, there was a virus that made monsters ill and go mad. Humans could carry it but not be infected. After monsters were sealed away the virus went dormant. Many years later, Alphys was experimenting on the human souls, Flowey already had been created and she was just working on the test subject (the amalgamates) though little did she know, one of the souls carried the virus and she had just mutated it. She tried stopping it from spreading once she realized but it was too late... She never made it out and the virus spread. The underground became an apocalyptic wasteland. Though there are safe places for survivors. In this AU you, Frisk, had just fallen and now must pass through the underground as survivors try to protect you and others and the infected try to hunt you down.
|[Signs/Effects of the virus]|
Unstable and unpredictable magic
Gain the ability to have a certain red substance
Mentally insanity
High hostility
Leaking black liquid (Physical form of the virus)
Increased attack, strength, speed and endurance
Loss of pain
Infinite stamina
Can simulate abilities of a human soul (Randomly selected)
|[SANS]|
One of the few who became infected in the first few days. Required to help evacuate others and fighting off the infected showed he had great strength but couldn't keep up due to his short stamina. He mainly roams around Snowdin making random puns unless he sees somebody and attacks in sight. Though through his loss, Papyrus and Toriel became good friends, Toriel runs the ruins sanctuary while Papyrus stays in Snowdin looking for others to help while Flowey is helping them both.
Undertale The Insanity Virus Playlist
youtube.com/playlist?list=PLY-vm0iG4XfSICC9tVTgEGuMdVsHi5RCf&si=RIS5Ggv-vDplGyWp
HAPPY HALLOWEEN!!!
Believe it or not, I originally made this AU a year ago and waited to release it until this Halloween! Fell free to ask anything about the AU!
|[Credits]|
Undertale - Toby Fox
Undertale The Insanity Virus - Many Miles Hedgehog/Maxwell Power
|[Lore]|
Before the war, there was a virus that made monsters ill and go mad. Humans could carry it but not be infected. After monsters were sealed away the virus went dormant. Many years later, Alphys was experimenting on the human souls, Flowey already had been created and she was just working on the test subject (the amalgamates) though little did she know, one of the souls carried the virus and she had just mutated it. She tried stopping it from spreading once she realized but it was too late... She never made it out and the virus spread. The underground became an apocalyptic wasteland. Though there are safe places for survivors. In this AU you, Frisk, had just fallen and now must pass through the underground as survivors try to protect you and others and the infected try to hunt you down.
|[Signs/Effects of the virus]|
Unstable and unpredictable magic
Gain the ability to have a certain red substance
Mentally insanity
High hostility
Leaking black liquid (Physical form of the virus)
Increased attack, strength, speed and endurance
Loss of pain
Infinite stamina
Can simulate abilities of a human soul (Randomly selected)
|[SANS]|
One of the few who became infected in the first few days. Required to help evacuate others and fighting off the infected showed he had great strength but couldn't keep up due to his short stamina. He mainly roams around Snowdin making random puns unless he sees somebody and attacks in sight. Though through his loss, Papyrus and Toriel became good friends, Toriel runs the ruins sanctuary while Papyrus stays in Snowdin looking for others to help while Flowey is helping them both.
Undertale The Insanity Virus Playlist
youtube.com/playlist?list=PLY-vm0iG4XfSICC9tVTgEGuMdVsHi5RCf&si=RIS5Ggv-vDplGyWp
