Sonia belongs to

Samarkana
Sonia's strange friendship with the dieties of her world continues. They felt a little bad about accidently making Sonia almost destroy all of existance, so Arienhae gave her a Universe Tour. Unfortunately, she's a little absent minded herself, and she dropped Sonia off in the wrong universe.
Will Sonia survive a world fueled by Cartoon Physics?
Will she be able to restore herself back to normal?
Will

Depthdropper's Ally an Phoebe ever recognize Sonia?
This story references Sonia outgrowing the Universe, from the Sonia fan stories by

Answers above. Comments and feedback welcome below. Writing a story where the primary transformation was size isn't my usual thing, but I was inspired to write Sonia melting down the mountain, so hopefully I did her justice.