I'm not sure what to believe regarding the existence of aliens and other ETs.

But I've noticed a particular phenomena that has occurred time and time again with me: I'll be on the computer watching a video, or watching TV and an image will come thru the screen that appears just like the classical grey aliens, as commonly described. They have the bigs heads, small eyes, tapering into a skinny neck. In some instances, more then one will appear to me. I'm looking for opinions of those that know a lot about the subject. Do you think these are really grey aliens, or perhaps are they some other entity masquerading themselves as such? Not much creeps me out these days, but I must admit that these do. I've also occasionally seen them appear on walls when the lighting was a certain way.