SQUIRREL!
I like the idea of "100%" squirrel Grace having antennae, which fits with
established canon. I think I prefer the antennae sort of swooped back in this form, however. They could still be pointed forward if she wanted, but she just looks more aerodynamic that way, and that seems fitting for the 100% (99.9?)% squirrel form.
Not that I intend to show this form in the main storyline. Oh no. This is all a tease that will never be seen outside of sketch form! MUH-HAHAHAHAHAHA!!!