The Nightmare

The nightmare tipped its head down, silver tongue flickering in and out as it drank.
Perched on a stone across the pond, I watched the equine. In the dim moonlight, its violet coat appeared dark blue, while piercing green eyes glowed with an inner fire that chilled my heart even from this distance.
This was foolish. Since childhood, I had been told tales of how they fed on our fears while we slept. I had even been told that they were the cause of bad dreams.
But I couldn't bring myself to stop these nightly excursions. Ever since I first saw the nightmare three nights ago as it ran through the campsite, I had followed it to this pond.
And each night, it had drank from the pond and then disappeared deeper into the forest.
Even now, I saw it lift its head. Two small tusks hung from its mouth like fangs, their silver tips shining faintly as water dripped from them.
The nightmare turned, and walked between the same pair of thin saplings as it had on the previous nights.
Standing, I hurried over to the other side of the pond. However, instead of attempting to follow the nightmare, I went to the spot where it had drank.
Kneeling, I looked at the water.
In the inky blackness, I saw a flicker of silver.
Glancing behind me, I scanned the trees for the nightmare.
Nothing.
I turned back to the pond. The flicker of silver was dimming.
If I didn't act now, then it would disappear like the nightmare.
Iciness filled my hand as I reached for the flicker of silver. It swirled around my fingers, a jellylike substance.
Grasping some, I pulled my hand out.
Cold radiated from the silver pool on my palm.
With barely a thought, I lifted my hand and tipped the gel into my mouth.
Frost bit my throat as I swallowed. Tingling, I stumbled to my feet as the cold spread.
Backing away from the pond, I ran.
Tremors racked my limbs, and I hadn't gotten very far before a spasm brought me to the ground.
Bursts of light filled my vision. A terrifying weakness spread from my feet up to encompass my entirety.
From all around, indecipherable whispers filled the forest.
The frigidity that had filled me transformed into a blistering heat, and I screamed.
Halfway through, the scream transformed into a horse's squeal.
As quickly as it had begun, it ended.
Now numb and exhausted, I tried to rise.
But my body was gone. Instead of an arm, I found a violet limb that ended in a cloven hoof.
"Welcome, nightmare." A voice whispered, and I looked up into a pair of piercing green eyes.