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Nightmare Fuel: Smiley
Smiley's face.. just Smiley's face, its covered in blood and the eyes and mouth are stitched up. At one point we can see blood coming out the mouth.
The fact he can be summoned on the internet and that he will actually kill the person you want him to as long as you want them really dead is also very unsettling.
He will even go after you after he kills the person you summoned him to murder.
The reason behind it all, it turns out the students had planned an elaborate prank to spread an urban legend and make it stronger, nearly faking multiple deaths and nearly driving Ashley to suicide, all to spread their legend.