After living as a Mew for twenty years, Butters unexpectedly discovered that she was, in fact, a tapeworm-like entity nicknamed a "Wiretap" that had spliced into the neural network of a drowned Mew corpse long ago and made the body its own, living normally with fragments of it's memories to assemble a simple enough past.

Upon realizing this, she proceeded to take a few hours for some self-reflection, which was easy due to her unique ability to actually look directly into her own eyes. If her host had been dead this entire time, did that mean she actually died twice upon discovering the Mew was dead? Or was everyone's experience with that of the parasite within her? If she did not know she was pretending, does it make it all real or a dream? Was it all a lie, or a mistaken truth? And does she just forget about it, or accept an entirely new life?

... then she lost interest and decided to see how maple trees reacted with nitric acid in large quantities. Just another normal day for her.