the alien

 there are many unsolved mysteries on this earth, including Bigfoot, Loch ness kraken,vampires, werewolves, and lizardman, among which the most discussed is the alien. the biggest fear aliens have of human beings is that we don't know if they real or not. We don't know if they are friendly. I don't know how advanced their technology is. we don't know if there are aliens on our earth that exist. Alien is the collective term for human-like life outside the hypothetical earth, including sightings of UFOs (United flying objects) there are hundreds of sighting, including video photos and eyewitnesses 

.the most famous alien sighting is the Roseville incide.