“Earlier in the course, we enumerated the myriad effects that ambient mana may have on bovine evolution. For those of you who took AG666: Intro to Fire, Flame & Farming, you were taken out to a volcano and were able to observe such creatures as the Inferno Oxen and Blazing Minotaur. In this advanced course, we’ll be going over more unusual variants. Turn to page 235 of your textbook, where we’ll go over one of the most feared monsters that dwells within the hidden mists. Should you be traveling in that area, and find yourself suddenly in an empty meadow, beware…

An Invisi-bull might lie in wait.

--Ezekiel Cowbane, Master Rancher. Recorded Lesson from: “AG672: Bovines of Unusual Provenance.” AC 1723.

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"Alright, get ready to roll out."

I do a quick once over of my armor, making sure everything is still intact. A glance shows the others doing the same and Luna and I take point, heading towards the entrance to the levels below. The dim blue light filters from all around, and it is only the faint currents which shift the luminescence, causing shadows to waver in the distance. I perform a mental review of the previous battle, and I look down at my claws to verify the stealth skill is still active. Slowly moving a pincer through the water, I watch as the outline shimmers faintly.

I remember looking into the faces of the worms, noting their lack of eyes. Though my visual outline is hidden, it's possible that more obscure senses could easily detect us. I imagine that those worms probably had something resembling a tremor-sense of some sort. I resolve not to let my guard down. There's no telling what kind of weird skills or abilities corruption might throw our way.

As I reach the entrance, I look down a descending slope. The passageway is a smooth bore hole as well, and reviewing my mental map of the area, I realize that there must be a series of natural caves in the hillside. It was only the worms that had connected them via their digging. Luna hops onto my shell and we start our descent. We walk in relative silence, my attention forward as I do my best to muffle the vibrations caused by our passage through the water.

Our journey has just begun, yet I can't help but wonder what the enemy is trying to do. Sergeant Smith said that at the front lines they are launching a major offensive, and I can believe that with all the fighting I saw. I'm not sure I'll ever forget those frozen images, backdropped by the sounds of explosions.

I tear my thoughts away from the cold memories and focus on the situation around me. We're coming up to a new entrance and as I call the squad to a halt, Luna and I sneak forward. As we get closer, I realize that this entryway is actually further up the wall from the bottom; it doesn't lie flush with the floor of the cave. It does give us an overwatch position however, and I'm easily able to look across almost the entire area.

The cave is similar in size and shape to the room we left a few minutes ago, yet there is one major difference. To the left of my current position, next to where the map says the entrance to the next area will be, the stalagmites lay sundered and ruined. A battle must have taken place over there, and as I look closer a strange square pile of stone meets my gaze. I'm unable to get a clear picture, the light is too dim, but with no movement detected, I call the others forward. Sergeant Smith joins me, and I soundlessly point a claw at what I noticed.

He takes a moment and then mumbles,

"It looks like they were doing some kind of construction work? We'll investigate. Keep your eyes open."

I manage to choke down a snarky reply. I'm a crab, my eyes are technically always open. Well... unless I get sand in them, but that usually only happens when something sad occurs. Sand is normally okay, but sometimes it can be annoying. It gets everywhere. Anywho, back to scouting. I scuttle out into the open water and gradually float down, using my spinnerets and [Water Manipulation] to control my fall.

Right before landing, I harden the earthen floor; making sure there isn't a sudden *poof* of sand into the water. My legs absorb the impact and I scan my surroundings to ensure nothing is getting ready to pounce. The coast seems clear, and I wave a claw forward. Nothing threatening immediately jumps out at my perception; the presence of the glow-moss letting me see details at a distance.

The squad falls in and I start to make my way through the room, dodging rock formations and leaving the broken area for last. The exit should be in that location, so it's a good place to save until later. The room is eventually cleared, and recalling the map, I realize we're two rooms above where the map ends. Idly, I note that the mission should be pretty quick with the lack of places to explore. Though the problem lies in whatever is outside the bounds of the already surveyed area. There's no telling what corruption might be planning there.

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I lead the squad onwards and we arrive at the sight of the battle. Broken rock formations hang from above, and those reaching from below lie in shards upon the floor. I glance around and head towards the blocky structure I saw earlier. What I find are rocks, but on closer inspection I can identify what Sergeant Smith was saying. The stone appears to be constructed somehow, either through skill or magic. The earthen materials are perfect squares, and they're stacked in rows ten cubes deep and high. Each cube is about as tall as I am, making the stack quite large.

As we draw closer, I notice the coloration is different from the surrounding material. Other than that, a quick visual inspection reveals that everything appears to be fine. Further testing is required, so hesitantly, I extend a claw to tap the stone.

*tink*tink*

Huh.

The sound is sharp, almost like tapping on metal and my claw extends once more. I try to gouge out a piece of the rock and my efforts are rebuffed. The material seems to be incredibly hardy and durable. Sergeant Smith says,

"Crabby, Report."

I reply,

"It looks to be stone of some sort. It's unusual though, extremely tough." I decide to try [Earth Manipulation] on the strange material, seeing if I can manipulate it. The stone barely deforms in front of my eyes, and it’s as if I'm struggling against an immense load. I reach out towards the block and anchor my legs into the floor. I grasp a stone with my claws and prepare to try to pull it away from the stack.

Remember Crabby, lift with your legs, not your shell.

I pull outwards and the stone just sits there, stoic and defiant at my efforts to budge it. I add my [Earth Manipulation] to the mix and I manage to pull it about an inch into the water. Gasping, I release my death grip and report once more.

"I think.... I think this might be some kind of highly compressed rock. It is incredibly dense and heavy. I don't know who would make something like this."

At my report, Sergeant Smith joins Luna and I while the rest of the squad pulls security. He looks at the stone and comments,

"This is a new addition. There was no mention of this in the previous reports." He thinks for a minute and says, "I've heard of some construction types doing this, but not only for building. They'll compress stone to make it easier to transport in a smaller package."

I reply,

"Even still, whatever was moving this is incredibly strong."

"Or has a high-level skill specialized for this kind of thing."

I nod and Sergeant Smith waves for me to continue scouting. The entrance to the next level is to the right of us, and for lack of other options I make my way there. We skirt the edges of the compressed stone and when reaching the backside of it, I notice a small recess. It's small, perhaps big enough for a single one of us to explore. Pointing a claw, I draw everyone’s attention to it and move forward to investigate. With caution, I peer into the hole and stretch my vision, trying to make sense of the interior.

As I look in, I realize that what I thought was a stack of cubes is actually hollow. The cubes are just a shell around an interior, and I try to make out what's inside. I flicker my [Mana Sense] on and only a grey blanket is revealed. I frown at the blocks of compressed stone; they must have some sort of mana suppressant effect. I return to visual inspection and struggle to make out details. The only light I have is from the glow-moss in the area. As my eyes slowly adjust I can see an outline of... something. I call over the comms,

"This thing is hollow inside. I can’t make it out, but there might be someone within."

Sergeant Smith edges closer and I step back so he can get a closer look. After a second he calls out,

"Alright. Be on guard. I'm going to release a mana pulse to get a better look into the structure. I'll keep it as localized as I can, but it may alert an enemy in the area."

I join the others and pull security. A second later, a faint pulse of mana ripples out and I hear a faint *click*. It's minute, and I wouldn't have noticed it if I wasn't straining my hearing, trying to pick up anything around me. Sergeant Smith says,

"It looks like someone might be trapped in there. They're unmoving, nonresponsive. I've tried hailing them on the communications channel but they're not responding."

Okay. I think back to trying to move the stone from earlier. If we all chip in, maybe we can expand the entrance. Sooner than I’m able to propose a plan Sergeant Smith says,

"I wasn't able to get a firm picture of who might be inside, but we have a duty to investigate."

For some reason I feel a sinking feeling in my stomach. I don’t know if the isopod is too tired to think straight but venturing into a strange box doesn’t seem like the smartest idea to me. I turn, ready to scout out the interior. But before I can voice my concern, I hear a deep sigh.

"Remain in position Crabby. I'll go in and have a look."

The Sergeants voice sounds tired, and I sneak a glance at him. He's hunched over, slumped and I can see that he's moving sluggishly. He climbs into the hole and begins to outline his actions.

"Entering the structure now. Moving towards the creature. I see multiple wounds, no bleeding. Identification is positive, he's one of ours."

A brief swell of pride rises in my shell. We can get him out of here and then... wait a second. What was he doing in such a strange contraption to begin with? I tentatively call out,

"Hey Sergeant... I think maybe..."

He cuts me off,

"The soldier is deceased. Securing the body for transport."

I feel a quick pulse of mana and identify it as the body being added to Sergeant Smith's spatial storage. Then another stranger wave of mana crosses through the water. My stomach seems to rise into my gullet as bright red lines course along the floor, linking up and shooting towards the compressed stone. I yell,

"GET OUT! IT’S A...."

I never manage to finish my sentence.

The entrance slams shut with a resounding boom. As I watch, the cubes instantly melt and reform; fusing with each other and forming a solid wall. Racing towards the edifice, I slam my claws into the side, trying to breach the exterior...

To no avail.