Jeff the Killer is one of the internet's most enduring Creepypasta characters, first surfacing around 2008 on Newgrounds and 4chan. The character is defined by his ghostly white skin, lack of eyelids, and a grotesque smile carved into his cheeks, accompanied by the chilling catchphrase 'Go to sleep.' While originally intended to terrify readers in short horror stories, the image became a cornerstone of internet culture, evolving from a genuine 'jump scare' to a versatile meme template. Today, it is frequently used in 'cursed image' threads or to represent the feeling of being wide awake and unhinged during the early hours of the morning.