Something must have gotten lost in translation. Apparently, in the third stall down on the third floor girls' room... everywhere... there is a lost ghost called Hanako. Don't go into the bathroom in that stall, because if you do, she will pull you into the toilet with her.
I would imagine that Hanako's parents would have reported her missing by now. One comment noted that the Japanese have a high-tech solution for everything and probably just push the button to flush when this comes up.
Ghosts don't inhabit boys' rooms, though. Snakes and possums and butt-eating monsters like to go there (get your post-it note out; when you scroll to the bottom of the article there are naked ladies' butts. fair warning...). When my little brother was small, he was afraid of a snake that would come up through the toilet and bite him on the rear end. My mom was mean to me and wouldn't let me tease him about it, either. She also made me give up ALL MY MONEY to my little brother after I traded him my big GOLD pennies for his little silver dimes. We were both happy with this deal until my mom TOOK MY MONEY, all of it, and gave it to my brother. It was my life savings. *sniff*
One final link: If you're travelling, you'll want to consult this website about where to find a public restroom anywhere in the world.