Okay so just by listening to this remix I came up with a silly Undertale AU.
Basically it’s a Castlevania X Undertale idea that I dubbed Undervania (I was also thinking Castlovania but that sounded stupid)
Basically it’s the story of Castlevania, where Frisk is the next in the Belmont line to slay Dracula. The thing is he leaves The Vampire Killer at home and decides that maybe he can convince Dracula to go against him destroying humanity to end this cycle once and for all.
I’m not a huge Castlevania veteran so all I can think of is Flowey as Dracula, basically being a cloaked vampire-plant monster where his entire body is made up of bloody spiked vines and plants, and Asriel is his final form.
Most people would think Asriel would just be Dracula by default, but I like imagining Flowey as this tall, dark and demonic looking Flower Vampire.
You guys are more than welcome to come up with more character parallels.