That Senpai's form is scarier than usual, so i think it's safe to assume that that is her actual true vagrant form, and the cutesy fish-like form from before is the controlled peaceful form thanks to the band-aid charms. Now i kinda wanna see how nightmare-inducing Senpai's uncontrolled form is.
Also, this chapter makes me realize that Funatsugi-kun has always has quite a pair of buttocks, doesn't he? I mean, it's even noticeable on the cover! O_O