I've done lots of reading about alien/UFO phenomenon, and have somehow missed the stories of so-called "grinning men" up until now. Really interesting and somewhat freaky stuff... especially since there are a wide range of these stories from people all over the place... all of whom don't really have any connection with each other.
http://mysteriousuniverse.org/2011/05/the-grinning-man-alien-apparition-or-mib/
Eyewitnesses claim that the Grinning Man is a looming figure who stands well over 6-feet tall. His head is said to be devoid of any hair and his dark, beady eyes are nestled unnaturally far apart in his domed skull. Some observers are so perturbed that they are later unable to recall whether he even had a nose or ears, but — as disturbing as that may be — far and away his most disconcerting characteristic is the wide, hideous, shark-like grin that is perpetually plastered across his face.
http://mysteriousuniverse.org/2011/05/the-grinning-man-alien-apparition-or-mib/