(After playing with Flandre, Marisa returned with a bite marks on her hand.. You asked her how did that happened..)

Marisa: "Ah? These? It's just Flandre accidentally bit me while we were playing. But no worries, Im all fine!"

(However, after a few days.. She seemed to change in appearance - Turning a bit paler, her golden eyes turn crimson colored and fangs visible when she talks.. You tell her that she changed)

Marisa: "Whaa?? I'm a vampire?? But- But Flandre told me it is not possible, ze!"