There is, in a small national park somewhere in the US, a bike path. This bike path is hardly unusual: it is roughly twelve miles long, and makes a circuit around a small lake. Most of the path is wooded, and it is regarded by the locals as a beautiful little place to take a breather and catch some peace and quiet.
Many who jog or bike along the path observe nothing out of the ordinary. But there are those lone bicyclists who happen across the Runner.

Mark coasted his bicycle to a stop on the side of the path. Standing astride it, he drank eagerly from his water bottle. Finally, he was able to enjoy a day off, instead of staying home and paying bills, or mowing the lawn, or fixing the roof. And he was at the park at the perfect time, too: he was practically the only one there, besides a few families in the picnic area and the old men who fished from the pier.
Wiping his mouth on his arm, Mark put the bottle back and was about to pedal off, when someone ran up behind him.
“Nice day, eh?” the young man said. He was tall and thin, and wore a hooded grey sweatshirt and black running pants. His face was concealed by a scarf and sunglasses. Since summer had yet to take the place of the mild spring, Mark saw nothing unusual about this.
“Yeah. It's perfect out.”
The young man nodded. He swayed when he stood still, as if he was anxious to keep moving.
“You up for a race?”
“A race? That'd be pretty unfair.”
“Maybe. But so is life, you know?"
Mark couldn't help but chuckle.
“Okay. You're on. Where to?”
The young man thought for a moment.
“Right past the tenth mile marker, by the old storm shelter.”
“Fine by me. That's a pretty good distance from here, though. You sure you can keep up?”
“I'll give you a ten-second head start, even. Just go whenever you're ready.”
While Mark did host some suspicions about the strange young man, he brushed them aside. Sure, he was a bit odd, but he seemed nice enough.
Mark put his foot to the pedal and rode off. His speed was almost casual, and with good reason: the ten second head start would let him build up enough speed to leave any jogger in the dust.
“You know, you're going to have to do much better than that.”
Mark looked to the left to see the young man there, keeping an equal pace with the bicycle without moving at much more than a light jog. The ten seconds had achieved nothing.
How did he do that?
Mark immediately shifted gears and began to put some force behind his pedaling. The bicycle shot off down the path. Mark kept his head low, cutting through the air with aerodynamic precision. The wind whipped around him, filling his lungs with cool air. The trees went by in a blur of green and brown. He kept pushing himself further, faster, faster, faster. There was no way the jogger was anywhere close to him.
Turning his head to the side, Mark saw to his dismay that the young man was still there, matching his speed perfectly. But now he wasn't even running on the path anymore: he ran straight through the woods, dodging obstacles with the grace of a deer. Actually, it would be inaccurate to say that he even ran. He flew. His feet barely touched the ground before he took another leaping stride forward. His scarf waved behind him like a tail. The way he ran, Mark could imagine him laughing.
Mark's amazement at this was numbed by the overwhelming sensory maelstrom his speed had achieved. There was no noise but the wind in his ears, no taste or smell but the chill air in his mouth and nose, no sight other than a stripe of grey in a sea of green, nothing to touch but the handlebars.
Then, the shelter appeared up ahead on the side of the path. The finish line. Mark looked off into the woods. There was no sign of the young man. He must have left him behind. Redirecting his gaze towards the shelter, he gasped and hit the brakes, hard. He screeched to a halt in front of the old wooden storm shelter, twin streaks of rubber burned into the path behind him, and the young man standing in front of him.
“Nice effort there,” he said, not the least bit winded. Mark on the other hand, could not reply due to his shortness of breath. “I almost thought you were a lost cause at the beginning, but you pulled through for the finish. Best race I've had in a long while.”
“H-how…how did you…do that?” Mark panted.
“I really don't know what you're talking about. But anyway, here's your prize.”
“What prize?”
“Your consolation prize, of course!” The young man almost sounded insulted. “I can't let effort like that go unrewarded. So much better than the others.”
Mark's vision began to warp. The forest seemed to grow darker, unreal. The young man seemed to loom larger, and more mysterious. Shadows and shapes that should not have been there appeared in the forest. Bodies. Dozens of them. Bodies impaled on saplings, bodies with heads smashed in by rocks, bodies torn open by some ungodly force, bodies hanging by their own entrails from the branches of trees. A row of bloody bicycle helmets were perched on a fence of sharpened sticks. They were there, and they were not, shifting between the real, the imagined, and the forgotten.
“Here's your prize, a word from the wise,” the young man said, in a voice textured the way no man's was. “The one who does not give his all receives nothing but his grave.”
The Runner walked into the shelter and was gone.