READ FAQ BELOW BEFORE COMMENTING! Exclusive to the Switch version. This video contains the full fight, so if you want to experience it for yourself, don't watch the video.
The Mew Mew doll is located behind the dog shrine. You can only access the fight when you're near the end of the game (after you beat Mettaton EX).
FAQ
Q: iS tHiS rEaL?
A: Yes.
Q: sPiDeR dAnCe!!
A: Not a question, but yes.
Q: Is this Mad Dummy?
A: Yes. Possessing Alphy's Mew Mew Kissy Cutie statue.
Q: How do you have 30/20 HP?
A: The Snowed Inn in Snowdin can bring your HP above maximum!
Q: What happens if you kill her?
A: You destroy the girl statue, but since Mad Dummy is a ghost, they can't be killed.
