"Bonetrousle (Beta Mix) - Undertale" is a high quality rip of the beta mix of "Bonetrousle" from Undertale.
This rip is just the song "Unfounded Revenge" from MOTHER 3. It is not a remix or a mashup of any sort and the advertised track is nowhere in this rip.
There are a few possible explanations for this rip:
- Both "Unfounded Revenge" and "Bonetrousle" are in the key of C minor.
- "Unfounded Revenge - MOTHER 3" does the opposite joke and uses the melody of "Bonetrousle".
- Undertale was largely inspired by the MOTHER series.
- This rip could be a reference to the Sans is Ness meme.