Have you seen a lot of your friends' pictures turning into giraffes lately? It may be because they answered a riddle incorrectly! It's called The Great Giraffe Challenge, and it's taking over Facebook.

Here's how the post might look on your friend's page:

(facebook)

Then you're supposed to message that person with the answer. If you get it wrong, you're supposed to change your profile picture to a giraffe.

Will it change how you live your life? Probably not. But do you know why in the heck everyone is changing their profile picture now? Yes. Yes you do.

But...do you know the answer?