The lowest sub-basements of the castle were ancient, dating back for thousands of years. Some areas of the dark, stone-lined corridors were wet, slimy, full of all the growing things that shun the light—other parts were dry, dusty, with stale air and way too many spider webs. Either way, most of them were unexplored in the last few centuries, only the few scant corridors that the guards still patrolled kept clear.

Sometimes, the patrol was assigned as a punishment—but normally the assignment of lower-level patrol was simply doled out fairly, everyone taking their turn. At least, this was the theory. In reality, the nightly barracks card games had the lower-level patrol as one of the most hotly contested stakes, winners getting to pawn the miserable task off onto the losers.

So today, the two guards wandering the halls were not happy about it. The two unicorns had white coats and blue manes, their cutie marks hidden by their ceremonial armor.

"I can't believe it. I would have sworn he would have a six!" one was complaining. "I can't believe I'm stuck down here again! I've had this job four times over the past two weeks!"

The other pony sighed softly. He was all for just enduring this stoically, perhaps discussing the latest hoofball game, but the first pony just wouldn't stop going on about how unfair it all was.

"And you know it's not good for our health!" the first pony went on. "All this stale air and mold... lots of ponies who take this assignment are getting sick! You know Silver Standard? He had this patrol yesterday, and he never showed up for work this morning!"

The other pony sighed again, plodding along like they always did, blocking out the noise as the other pony kept going on, and on, and on, and on. He glanced down a side hallway without thinking about it, kept walking, then paused, one hoof lifted. "Wait," he said. "Was that a light back there?"

"And then she said, Oatmeal, are you crazy? ... What? Light? Where?" The first guard backtracked and looked. "Hey, it is!"

The two guards trotted down the hall to investigate, where a soft, flickering light was shifting from blue, to green, to pink, and so on. They peered around the corner, the glow of the light coloring their white coats.

"Well," said the second pony, "I've never seen the like. What on earth is that?"

"Dunno... give it a prod!" said the first.

The second unicorn sighed, and his horn glowed as he telekinetically prodded the strange thing. Both the guards' eyes widened... "Wh... what?" asked the first.

"Quick, hold them back!" cried the second. Both unicorns' horns glowed, as they tried to keep back the skittering, whisper-quiet sound of hundreds of creatures. Blasts of magic shot forward to splash into the oncoming glow, to no apparent help.

There was a terrible, horrible pair of screams.

There was a terrible, horrible silence.

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