Slenderman was bored.
He hadn't killed or abducted anyone in 3 days, and had taken to wandering the woods in hope of finding some people to murder. The last people he'd killed were about to reach the edge of the woods until they read a note stuck to a tree. One of Slender's notes. He'd heard them express their relief that "it" was gone forever. Slender didn't know what they were talking about, nor did he really care. The married couple could now be found in the trees, organs hanging down like streamers.
He'd reached the middle of a small field with high grass. It was quite beautiful, really. He started to turn away, but paused.
He wasn't alone.
In the middle of the field, there was a small presence. Miniscule, actually.
Slender was confused. Why hadn't he noticed before? Surely he would know if something wasn't right in his territory. He made his way toward the presence, and was surprised at what he found.
Clinging to a blanket was a baby, barely a year old. It was shivering in the cold night air, and he could hear its ragged breathing. Slender knew the child was dying; he could feel the life force of the child slipping away. He didn't know how long it had been here, nor did he know why. Hesitantly, Slender extended a tentacle from his back and reached it toward the child. The tentacle brushed the baby's chest, and stopped as Slender heard a near-silent giggle.
The child was awake, barely. Contrary to popular belief, Slender could see without eyes. So he directed his gaze to the child's face, and was slightly dumbfounded at the fact that the dying boy was staring at him, and smiling. The boy's eyes were slitted, like a cat's, and he had a lone canine tooth poking out from his lips. He gave a giggle that was mixed with a cough, blood staining his chin. The boy wouldn't last much longer, and Slender decided that he needed something to do.
With no hesitation, the tentacle pushed some of his own life force into the near dead baby. Slender knelt down and picked up the child, wrapping the blanket securely around his body. Wiping the blood away from the boy's chin, Slender cradled him in his abnormally long arms and walked off into the trees.
Ten years have passed, and the Slenderman hasn't been seen since that day.
Not yet, anyway.