We've all probably done it. After a long day at work or a rough night at the bars, plenty of straphangers doze off on the subway.

But the next time you feel your eyelids getting heavy as you ride the rails, keep in mind that you may wake up with a rat on your face.

Yes. That's what happened to one unsuspecting man who was catching some zzz's on the 4 train near the Franklin stop in Brooklyn. A rat crawls up the outside of the man's pant leg and goes right up to his mug before the rat's victim wakes up in horror.

After the rat scurries away, the man tries to play it cool and assures the camera man, "I'm fine."

But what about us? Are we fine after watching this? No. And what's worse is that we just pledged our salary to cab fare. Or maybe this is nothing more than a viral campaign that will eventually urge us to buy rat protection? Whatever it is, we will buy it.