As simple as it sounds, these are the AUs in which every character is the same person as every other character. Of cause this brings up questions like, is the Undyne in the Captain of the Guard role in Undynetale the same as canon Undyne or are they the Undynest Undyne in the multiverse (or an amalgamation of every other character, as she is "everyone"). We may never know.
These are comedic in nature and rarely make much sense beyond amusement value.
Pages in category "AU where everyone is the same person"
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