[Ishimaru gives his own confused stare back, and he blinks as he tries to make sense of that.]

...Ah... I see? I would not want you to expend any unnecessary effort when you could put such energy into your studies, though I do have the time and will to hear out whatever you might want to say! You must be referring to some manner of urban legend... [He concludes. That would explain why he hadn't heard of it! Such things go under his radar.]