Sudden Changes is an Undertale AU created by Spouting, along with help from various sources which are credited in the respective parts where their assistance is noted. The AU features an on-going comic, in which the first part was posted in October 2016 and is still continuing today.
About the AU
Sudden Changes is a role swap AU following the basic rules of Storyshift with only the lost souls, along with Mettaton, Napstablook, Chara and Asriel changing positions. The AU Scramble Saga was an inspiration and helpful for finding a standard of quality the author would be happy with. The author also answers in character asks on the official Tumblr where characters within the story respond to non-spoiler questions.
- The RUINS map itself is changed with the addition of a gigantic hub room. This room leads out into the room Napstablook is found in Undertale where it shows Undyne giving a Whimsun basic music lessons.
- The Spider Bakesale has moved on to location in Snowdin.
- Asriel is the caretaker of the Ruins, and appears to have been listening to a talking flower before seeing the Human.
- Flowey is introduced in Part 6 instead of at the beginning.
- Asriel lives in "Our Home" (Home (Also known as "Toriel's House") but remained due to alternative universe variation and different choices) with Toriel, who is alive, albeit being older due to having to deal with giving Asriel her soul energy for him to grow up. Asriel is the one you fight near the entrance to Snowdin rather than Toriel.
- Flowey is still called Flowey, but he is bigger than his canon counterpart. He also has a black "shadow" over his face which he uses at will, and refers to the Human as a "conqueror."
- Toriel now takes a minor role, but she is still a caretaker (But together with Asriel).
- Sans now wields a gun in the "Genocide" ending, along with also being more energetic then UT Sans, due to Sans drinking coffee