I've never seen one so I can't say that they do exist, but I also realize that just because I haven't seen one doesn't mean they don't either. Just as you saying they don't possibly exist doesn't mean they don't. To view the possibility that they do exist as nonsensical is rather conceited and to not even consider it a possibility is nothing more than a closed mind, and to me common sense does not coincide with a closed mind.
And if all you see here is a bunch of people who want to believe in something that clearly doesn't exist, you are not looking closely enough. There are many sceptics and even the many who know or believe don't automatically take all stories as gospel.