Narciissus
Age: Unknown (first reports date back to 2006)
Gender: Unknown (male-presenting)
Species: Unknown
Bio
The entity that would become Narciissus started out as a urban legend of a "evil Mii" that would appear at random and massacre the victim's Miis.
People believing that it was real gave it sentience, and people adding onto the rumor made it stronger and more aggressive.
It is not a rogue AI or a ghost. It is an egregore, a entity born from the collective thoughts of a group of people. In this case, it was born from the collective thoughts of young, gullible gamers.
It feeds on people's fears as well as the "flesh" of virtual avatars. It is extremely unsympathetic and never stops pursuing its prey until it catches them.
It once exclusively appeared on the Wii's Mii Channel, but its range has since expanded to include any game/system with customizable avatars. It has well over 100 known forms. The most infamous one being a white-shirted default Mii with a toothy grin. The form described in the orignal rumor.
It currently appears to be attempting to find a way to physically manifest itself in our reality because it refuses to be known as "just a playground rumor".
Description
Most reports describe it as having the look of an unnamed default male avatar with plain white clothing and a toothy grin. It is believed that this unsuspecting apperance is the form it takes on in order to lure in its victims. Users have reported not being able to delete or modify the avatar in any way.
One of its "true" forms, according to some first-hand accounts, is described as being a completely white default male Mii with wing-like appendages on its head and additional sets of arms and eyes.