I once heard in a shiur from Rav Tzvi Aryeh Rosenfeld in which he discussed that if a niddah looks into a mirror that nobody has ever used before then it will get a blood spot on it
To go totally off topic, why is this not the same as other zany ideas that other religions have (and we make fun of them for it for being so outlandish), such as the 72 reBesulosing Besulos, or transubstantiation?
Serious question, not trolling. If we can accept the supernatural/unexplained that we see does not happen as fact, why should we disbelieve when others claim the same?