Well, this is HORRIFYING. Rats are able to crawl into your house from the damn toilet?! Oh HELL NO! Apparently this is a real issue and not just an urban legend. Especially if you live in the basement or on the first floor. Gothamist contacted Eddie Marco from Brooklyn Pest Control and he had this to say:

I’ve dealt with it many times. The pipe is empty, the rat crawls through the pipe and up over the hump and into the porcelain. And he can’t get back out. What I do? I flush it down! It happens all the time, especially if you live in the basement or a first floor apartment. As soon as they go up over that hump they’re in the bowl. So they call me, I go in and just flush the toilet. 100 bucks!

Gross. Watch the video from National Geographic to see just how the little monsters do it.