facebook

I don't understand why anyone would even want to do this sort of thing. They clearly have way too much time on their hands...no job...live in parent's basement...that sort of thing. But some people will do this just for entertainment, I guess. They can grab any info that you make public in fb and run with it, creating entirely new profiles with your name and picture or whatever. Then they start friending people already in your friends list, so they can grab their info as well. Then they just get nasty and send weird stuff all over the place.

I think Facebook has been part of a persons egocentric preference so I think that's one reason why we cannot understand some actions people do in Facebook.

I agree with @owlwings, perhaps the account was hacked. If you're certain their account was not hacked, perhaps the person is having some moments. You can ask him/her directly if you can. Anyway, there are also online predators that one should be wary of. So, look out for these types of people. Good luck!

any messages that you do not have to believe and also lock your profile to no such surprises.

Maybe they hacked the account. It also happened to me several years ago. My Yahoo account sent a message saying I'm selling Viagra. It was sent to all my contacts. I learned about this because one of my friends asked me why I sent that message. I sent an apology letter to all my contacts.

Your friends Facebook account has most likely been hacked. :/