never responded to this (shuffling through my mind to remember everything that i originally wanted to sayy), but this makes perfect sense!
an already existing environment that'd really get your mind in that really cool creative headspace + the right amount of pressure... if that spring break to show your teacher was a significant enough of a pressure??
your subjective experience while making the melody also makes sense!
i suppose that it'd be like having learned a language (even your native language), and you figuring on the fly what notes would sound best next would be like figuring on the fly what word next to say in a sentence??
like, the process of what the next note/word should be isn't random as you shuffle between notes/words, but it wasn't pre‑constructed, either.
and oh my gosh, i totally see what your friend meant with the undertale waterfall bit, aha!
just sang it over your melody.
similar kind of staccato‑y effect, and similar upward movement in pitch to move the tension, and all that??
singing over it also made it clear just how different yours is, too, though, even if some of the underlying musical language have similar roots.
subconsciously learning from the skills of others via that whole ”great artists steal“ thing and suchh
and yeahhh, you were the one who made this, so the internal aspects of what gave rose to this song's definitely still there + a few more years of experience!
probably can't perfectly reproduce the same conditions that allowed spook1 to come about, but you don't need to???
since there will be other conditions to lean onto as you continue to build yourself up with more and more experienceee
and even if luck had played a role tbh you can study off yourself (even if subconsciously) and possibly figure out how to produce certain effects you liked more consistently with enough experienceeee
it still came from your mind and all that, after all!!
good luck with your music and other creative stuffs, but also with college!!!
and also enjoy the rest of the spooky month since i took so long to reply, eheh.