I think it would be fun to make her fight either Cuphead or Mugman, especially since it is hard to gauge how bosses with multiple phases work, in the game you can overdamage them between phase transitions, some are easier to do then others, and I believe Sally herself is not one where you can over damage that easily.
That said, Sally is not a hard boss, she doesn't have a lot of projectiles on screen and the battlefield doesn't move that much, I don't know how good Globule's acrobatics are, but you honestly don't need a lot to dodge most of Sally's attacks, baring the Tsunami from the third phase. Hitting Sally is also not easy on her Last Phase, if Globule has double jump that can help, but even without it, Globule has a 1.76x AP advantage, so it shouldn't take a lot.
Honestly, there isn't a lot to say outside of "Sally is not a hard boss, none of the bosses have lore or anything going for them outside of their game mechanics" and Globule, which I assume is from a platformer, shouldn't have any issues with her, and that is likely true for most protagonists.
Once again, I think either Cuphead or Mugman would be more fun to argue for, but overall I would say Globule should take this without much trouble
