This thread is an example of why, in my opinion, bigfoot is the most interesting and scary of the monsters.
Vampires, werewolves, mummies, etc, all have a strict comic bookness about them. Fantasy stuff. Fun scary movies, but no substance.
However, when we talk of bigfoot, you get rational believers and plausible stories. Hair raising reality. Is it real or not? Hard to say for sure. Ok, lots will say not real at all. But you could still tell them a story that will make them think twice