I’m probably the last person you expected to post about this, aren’t I?
ANYWAYS.
I’ve been listening to a couple of fan penumbra phantasm covers recently and holy crap it’s a good motif. I decided to do a little looking into the whole “penumbra phantasm in deltarune” thing, and saw very good arguments for both sides. One thing several people said though was that Toby said he wasn’t going to use it because it used the Doctor motif, and the creator of that motif has sadly passed away. However, I couldn’t find Toby’s post or whatever that says that. Can anybody confirm whether that’s real or not?
What if Penumbra Phantasm is already in Deltarune and we just don't know
What if Toby just removed the doctor motif and made it THE WORLD REVOLVING? Don't Forget? The Legend?
At around 1:20 [in Hopes and Dreams], there is a reference to the song Doctor from Homestuck in the piano. Sadly, the creator of that song passed away, so as a respect to them, I will not do any more references to them in my work. There is no way for me to get permission.
Toby did say that about doctor specifically, but penumbra is pretty clearly related to deltarune and the fountains going just off the track name alone. Crack theory could be that the motif from the unused fountain theme could be a doctor replacement since toby specifically says he made the track to introduce a leitmotif (which is quite funny because he used the holy instead, a song that has a melody similar to one of penumbra's melodies)
So that does rule out penumbra phantasm in its current form, but it doesn’t seem to rule out the penumbra phantasm motif. Although, I did hear that penumbra phantasm was a modified version of the doctor motif - how close are they in reality?
Penumbra uses doctor as a motif, the penumbra phantasm melody is very much different and original, played on the guitar here. (this is from a recreation of the penumbra phantasm midi).