I'm guessing you have a smallish camera with the flash quite close to the lens and you also get that 'red eye' effect with it?
I'm afraid these cameras produce these things all the time and its only the flash reflecting off stuff floating in the air a couple of inches in front of the lens - if you think of a projector beam in a dark room and all the stuff you see floating in it, that's all it is - they look like round blobs because they are out of focus from being too close to the lens.Bigger cameras, or ones with the flash away from the lens simply don't get them because the flash can't light up that area a couple of inches in front of the lens.
The web is full of sites proclaiming that they are spirits and claiming to see faces in them, but its all wishful thinking from people who are not too hot on photography, don't ask too many questions and certainly, in my experience, do not want any answers!