The clink and clang against stone never stopped. Rocks ranging in size from pebbles to boulders were being pushed along designated paths and out to some unknown place. Exactly where the rocks were being taken wasn't of any interest to Trixie and Twilight. Still using their magic to make themselves invisible, the two were slowly and carefully making their way across the massive complex to investigate everything going on. It was a pretty challenging feat, considering just about any room to walk was already being used by one of the lifeless black creatures digging in the cave.
The smooth, gray rocks were damp from moisture in the cave. This interested Twilight. There must be a natural well down here somewhere, whether or not they dug it up on purpose, I can't say. The question is, would these creatures even need to drink any water? Twilight stopped suddenly when she stepped on a small section of clay. Trixie bumped into her backside a second later, having not seen the invisible pony stop.
Trixie wanted to tell Twilight off, but she knew that speaking right now wasn't an option—those black pony-copies were working but a few yards from her and Twilight. Trixie wanted to talk, because she wanted to ask Twilight just why the heck she stopped out of nowhere, and where the heck she was planning on going now. Only now did she realize that the two of them wouldn't have many opportunities to be able to communicate while down here in the cave. 'Hindsight' seemed to be a word regularly popping up in Trixie's head as of late, but her question was answered suddenly in a way she didn't expect.
Writing was magically being carved out of a patch of clay on the ground in front of her and Twilight. Trixie continued to watch the letters appear; she knew it had to be Twilight writing the message in the clay for her: 'Suspect water source nearby. Pony-fakes may need water, food. Let's try and find a well/stream.'
Trixie dug her hoof into the same patch of clay, and wrote a single confirming 'okay' to Twilight. After biting down on the tip of Twilight's tail again—to stay together—the unicorn duo continued down the path they were already on. Compared to the one large room of the cave, they were currently in a deep, narrow ditch. The cave itself was a good several stories tall, with a circular ceiling and floor. Within the floor of the room, there were plenty of said ditches dug deep down, bridges connecting the upper floors above. Despite looking very random and chaotic upon first glance, the digging method was actually quite well planned out and articulate.
Each ditch branched down and out of the main cave; into where, Twilight and Trixie did not know. There must have been thirty horizontal ditches sown into the floor, and they were randomly trying a single one. Hopefully, either all the ditches led to the same place, or the unicorns were lucky enough to have chosen the right one first.
Twilight and Trixie continued down the small tunnel, every so often bracing against the wall to avoid a dark pony walking up or down the same path. After a couple minutes of slowly and carefully making their way down the slippery dark trail, an exit to another room was within sight. The unicorns picked up their pace a bit to see what was ahead.
The two trotted out the tunnel and into the new room, which was even larger than the dug-out one they had entered from earlier. Twilight was awestruck once again as she tried to take in the entire sight, and Trixie couldn't help but utter a soft "wow…"
Instead of the horror they had just seen before, with all the black creatures digging away at the cave's interior, this place was much more serene. There were very few of the fake-ponies here, and unlike the excavation site from before, this cave appeared to have been naturally formed. The cave had a massive underground lake and was full of stalactites and stalagmites; a very warm, relaxing steam was emanating off the surface of the water. The two unicorns were thankful that they were invisible; someone otherwise would've seen how frizzy the steam was making their manes.
"I knew it," Twilight replied softly, to herself more than to Trixie. Trixie could hear just by Twilight's voice that she was pretty proud with herself.
The azure unicorn took a look around to make sure none of their enemies were too close nearby. After seeing the cost was clear, she came closer to Twilight and whispered, "I can tell from here that this water must be pretty hot. Why on earth is it so warm here, and yet so cold throughout the rest of the cave?"
"I don't know Trixie," Twilight honestly replied. "But let's take note of this, and of anything else we find out down here. Now's not the time for answering the questions, anyways; we can do that once we get back out of here and recollect our thoughts in Appleloosa."
"If you say so…"
Though the two had tossed the stained-glass mug, Twilight did happen to bring along a glass jar, which she and Trixie had been given among their pile of junk (Celestia knows why a jar…), and she took it out of her bag and dipped it in the pool, holding onto the jar with her magic. After filling the jar halfway, she sealed the lid back on and quickly brought it back into her bag. Their supplies, like them, were completely invisible, but Twilight still tried to disturb their surroundings as little as possible. "What now, Trixie?"
The young magician mare glanced around the natural spring. The entire floor of this particular cave was part of the lake, save for ten feet of shoreline that spread out parallel to the wall where the tunnels were. On a quick inspection, Trixie found that there were holes lined up among the wall—all the ditches on the left side must lead to the spring, for whatever reason. "I think, if we're here to investigate, we should watch these pony-imposters for a few minutes; see exactly what it is that they're doing."
"Good idea," Twilight replied in a low tone. "Y'know, I think we should create a name for these things, don't you think?" Since Trixie was still invisible, Twilight didn't see the strange look the mare gave her. "We're always calling them one thing or another—let's just make a name up."
Trixie shrugged and tilted her head back in amusement; again, not that Twilight could see her. "Whatever floats your boat, Twilight Sparkle."
"Okay…how about…hm. How about 'Odium?" Twilight asked Trixie.
"Odi-what? Where'd you get that from?"
"If I'm not mistaken, it's Latin for 'hatred'. I know how everypony says 'hate is a strong word', but I'm feeling some pret-ty strong emotions against them."
"Takes a bit of effort to say, don't you think?" Trixie once again felt that this was just Twilight trying to show off her vast knowledge of trivial facts, but even Trixie knew that now wasn't the time to start up an argument, so she let it slide. This time. "But again, whatever floats your boat. If you seriously want to call them 'Latin hate', be my guest, I'll even play along."
"Ooh, alright!" Twilight either hadn't detected the tone of arrogance in Trixie's voice, or she had simply ignored it. "Now then, let's go investigate the Odium!"
"Shh! Keep your voice down, idiot!"
As they neared their subjects, the two unicorns stopped talking altogether, and they slowed their pace, trying their hardest not to make too loud a noise when placing their hoof onto the damp stone floor. There were three 'Odium' standing right at the spring's edge, and they hadn't moved a muscle since Twilight and Trixie had first laid eyes on them from the other side of the cave, almost three minutes ago. They appeared to be staring out at the lake, though it was hard to tell for sure, considering how they had no pupils.
Their behavior was confusing Twilight. What in Equestria are they doing? They haven't even budged! Shouldn't they be working right now, digging rocks or whatever? It was pitch-black in the cave, and the only reason Twilight and Trixie could see right now was because of their night-vision spells, but how were the Odium able to see in this darkness? Were they actually able to see, or were they simply using their other senses to guide them? Far too many questions were buzzing in Twilight's head, and not even one was any closer to being answered.
Out of nowhere, the three black creatures began to move again, and like a robot suddenly being flipped on, they walked back into one of the tunnels, ready to work again. The unicorns glanced around to make sure there were no other Odium around, and after seeing the coast clear, began to talk to one another.
"What was that all about?" Trixie asked snidely, as if insulting the Odium's recent actions to be very stupid.
"Don't know…" Twilight glanced up the tunnel that the three had entered. "Let's follow them, up this tunnel. It's the farthest on the left of this wall here, so if I were to guess, it'd also be closest to—"
Trixie didn't need Twilight to finish her sentence. "We've done many a stupid thing today, Twilight Sparkle, but there is NO WAY you're getting me to go anywhere NEAR that massive black Odium thingamajig. Perhaps you didn't realize when you first saw it that it is FIVE STORIES TALL and sports TWO GIANT CLAWS that are JUST AS HIGH?"
"It looked really slow to me," Twilight replied defiantly. "Not the brightest bulb, if you catch my drift—our chances of getting caught won't change just because we go near it."
"Didn't you see the huge scratches dug in the walls around it? That's all pure brute force!" Trixie had taken a lot of crap from Twilight today; the purple unicorn had made all the important decisions, and the poor magician had little choice but to comply. Trixie had no choice but to draw the line at some point. "The Great and Powerful Trixie is NOT going to become your personal henchmare, Twilight Sparkle!" With a snobby 'humph', she twirled around to face away from her companion. "You can go ahead without me. Simply come back when you're ready to go somewhere that isn't there."
Twilight growled at Trixie at first, then she turned back to face towards the tunnel and away from Trixie, giving a 'humph' of her own in retort. "Fine, I'll go without you. Just try and not get caught, Trixie—we wouldn't want you to mess anything up."
The two invisible ponies took a moment to make several faces at the other, unaware that the other was doing the same thing. Afterward, Twilight began up the tunnel to more closely investigate the massive Odium they had seen earlier.
Trixie hadn't actually taken Twilight seriously; she thought that if she were to disagree with the stupid purple unicorn, that she'd have no choice but to do what Trixie wanted. Instead, they were now splitting up, and the thought of being alone down in the dark, desolate cave unnerved Trixie. Not even the warm, relaxing steam off the spring could calm her, but she'd much rather stand there idly than follow Twilight into a death trap.
Twilight shivered hard. As the tunnel's gentle slope rose, the temperature quickly fell. As she continued to walk, the warm humid air from down below quickly turned into cold moisture that stuck to her body. The sounds of striking stone began to ring again, and Twilight quickly found herself back in the first room she and Trixie had first entered. She was in another ditch, and could see three Odium working away at the walls. They must be those three we just saw earlier. I still don't understand what they were doing by the water, but I suppose that isn't important right now. As Twilight crept out from beneath a stone bridge up above, she could suddenly see the same giant beast from before. Since she was standing in a fifteen-foot-deep trench, not much of it could be seen from her angle, but what was seen was massive, smooth, and pitch-black, an ever darker black than that of the cave it was residing in. Twilight continued down the pathway, dodging the occasional Odium here and there as she went; she was trying to find a way to get even closer to the monstrosity. Perhaps it's a good thing Trixie didn't come along. If she hadn't objected when she did, she definitely would've by now.
Twilight continued down the one-way ditch, all the while keeping a watchful eye on the black ball hovering not to far overhead. It barely moved at all, only nudging its body to the left or right; most likely to get a better look at something going on in the distance. Unfortunately for Twilight, it appeared there was no way to get closer to her target—she ended up on the other side of the cave after two minutes of walking and scanning the trench she was in for an escape up to the upper level, but instead she ended up in front of another tunnel, just like the one on the opposite wall. Twilight shrugged to herself. Well, there isn't anywhere else to go.
Unlike the tunnel to the underwater spring, this tunnel was slanted high upward, and at a much steeper angle, too. There weren't even any steps for Twilight to get a foothold on. How do the Odiums manage to walk up such a steep incline? This must be at least a sixty-degree angle!
Almost as if on cue, Twilight heard steps from down below. She turned her head to see an Odium walking up the slant as if it was nothing, but Twilight quickly realized why. There were no sounds of hooves on stone as it walked, but rather a kind of squishing sound; Twilight could easily see the bottom of the creature's feet turn to goop as it pressed down on the rock. Duh, Twilight—these things are still made out of black slime. But in that case…why do they all look like a bunch of different ponies? Every single one had a different silhouette, and there seemed to be absolutely no purpose for doing so. Yet another unanswered question for Twilight; the lack of answers was really beginning to get under her skin.
Twilight stood still to let the Odium pass, and then she returned to her own efforts at getting up the incline. It took a fair amount of effort, but she eventually reached the top of the steep hill; it was only about twenty feet above the floor of the trench. She had entered a small room, small compared to the size of the previous two massive caves; it was domed, like the inside of an igloo, and was about thirty feet from one side to the other. There were four different openings, leading to four other tunnels, and there was a fair amount of traffic going through this specific area. Twilight had just heaved herself up a sixty-degree incline, and trying to mask her heavy panting wasn't exactly easy. In order to put some space between her and the unaware Odiums passing by, Twilight exited the room through the hole that led back into the main cave. Now, she could easily see the massive black sphere of a creature, sitting stoic on its stone pedestal.
Twilight was now on the upper floor of the cave. The cave itself must have been at least eighty feet from ceiling to floor, not including the deep trenches dug out of the ground; she was about level with the base of the giant Odium's wispy tail. There were very few of the smaller black beings on the top floor, and Twilight took advantage of such by allowing herself to breathe a little louder, and walk just a little faster. Curiosity was really getting the better of her, as she was eager to closely examine the wide-eyed ball only fifty feet away from her. Twilight trotted over bridge after bridge, slowing down while crossing each one, until she was finally up close with the enigmatic shadow. She didn't know what to say or do next. You've gone all this way, Twilight. Now what?
Thankfully, her question was answered when something near the Odium's tail caught her attention. As Twilight walked up to the floor where the tail met the stone, she found that it didn't actually touch ground—instead, there was a hole, not but four feet wide, that the tail continued down into. Surrounding the hole was a spiral staircase, leading down into the unknown. Twilight was just about to start down the steps until a thought grazed her mind. Trixie. I can't just leave her back there. But to go back now and bring her all the way back over here would take way too long, and who's to say she'd even come along? I could waste valuable time going back for her! Let's make this quick, Twilight—check down the hole, leave and get Trixie, and then we can get the heck outta here! Granted, they had made no progress so far on getting back Paula, finding the Sheriff, or even locating the black box, but Twilight and Trixie did have useful tidbits of information that could prove helpful to the civilians of Appleloosa.
Twilight hurried down the staircase. She wanted to know where the creature's tail ended, that's all she wanted to know. She'd simply find out what it was, and then leave-
When Twilight reached the bottom of the staircase, she promptly stopped in place, and had to plug her mouth with her hooves to cut the loud gasp she let out.
It was a small room, and it differed substantially from the style of the rest of the cave. Rather than the smooth, wet, gray stone of the cave's norm, this room had flat walls and straight edges. This was an actual room; the walls were carved out in bas-relief with diverse pictures and ancient writing, and one or two vines had somehow braved the odds and managed to thrive in this pitch-black, cold environment. But it wasn't the room that startled Twilight; it was the little black box, sitting on a cylindrical stone table two yards away, and a hole in the ceiling directly above with a wisp of black smoke descending from it, wriggling down and into the keyhole on the locked box.
Twilight's half-gasp alerted the two Odiums in the room as well. They had been standing off to each side of the table, perfectly still and staring forward, not moving an inch. The smoke had broke off into three separate streams, and while one went into the black box, the other two were going straight into the minds of the two Odiums. It took Twilight only a second to recognize their silhouettes as belonging to PaulaRed and Sheriff Silverstar.
It took only another second for the two possessed ponies to make a move for Twilight, attempting to drive her into the ground.