I looked at the 2 previous comments, I think this short series is a reference to a Junji Ito comic. I just remember a page of a person looking out their window and seeing a super tall person passing by
And now we got the real Hasshaku-sama throught ULiL Ichirin. To be honest, I haven't understood the story of this urban legend.
She's basically slenderman. She stalks and kills people who notice her waiting at abandoned bus stops, her iconic laughter is Po, po, po, which she chuckles while stalking her prey, apparently she has a sort of manly voice.