I'm probably just self projecting since I kin her, but I think Mabel Pines as Nebularomantic would make a lot of sense. She's very ADHD coded, and I think it makes her hyperfixate on "crushes" since the idea of it seems very interesting to her, which is why she randomly "falls in love" with someone randomly all the time — but she doesn't know the difference between a fixation from adhd and an actual crush.
It's okay if you don't agree, just a headcanon.















