I myself know for a fact that extraterrestrials exist, and I know they are among us. They have been in intimate contact with the organizations in charge of us, and many walk the streets disguised as humans.
I myself have actually seen one as a human in my school, and my mother saw one when taking her mother browsing old folks homes. Some wear it better than others, but overall you can notice a larger, more teardrop-shaped head, smaller teeth, an outward-pointing jaw, and a plastic-looking face. Their skin is naturally grey, but that and the head shape are the only similarities they share with the Hollywood "Greys". They have human eyes, and the rest of their body apart from their head is the same as ours.
I have suspicions of the validity of a lawyer local to Colorado Springs, name Mike McDivitt. Most photos of him on the internet will show some differences from what a human looks like, but he's a lot more extreme in person (from my landlady's experience).
There are a lot of other things told by many people who have had experiences with them. One of the people who went to the moon (and has since been assassinated) said that there were weird ships hovering over the moon watching them, which they were told to ignore. A few years ago NASA leaked a photo of a Klingon-looking ship about the size of Earth sitting next to the sun, and from what it looked like it was refueling. NASA's explanation was that it was a "sunspot" (which is ♥♥♥♥♥♥♥♥). There's also a rumor that they didn't go to the moon to simply "win the space race" (which is a load of crap); instead, they went up there to pick up some technology and bring it back down to Earth.
There's a lot of things regarding extraterrestrials that are hard to explain. A few will realize what's going on, others may deem it as baseless crap (as the government wants), and a lot of people outright ignore it out of fear. My personal experiences have opened me up to such anomalies.
Heh. I remember looking at him. He had an odd, rigid head that was huge, and was laughing when I noticed him. He had small teeth, and an incredibly pointy jaw. When I gave him a confused glance, he glared at me with little happiness. At that point I just dismissed him as an odd human; looking back I know exactly what he was. Now that I know what to look for, I can only see myself as a deer in front of a car when I next spot one: you can't run, you can't look away; you don't know what to expect. My only worry is what they'll do with a person like me with the knowledge of their existence. From what I've heard some are friendly, while others are not. Who's to know?