With the gestalt’s map in my head, it was easy to plan my route. Ants were naturally burrowing creatures; that combined with human-level intelligence and access to mana allowed them to thoroughly map out the underground for miles in every direction. Even dying did nothing to slow them down, not when the gestalt knew everything each individual ant discovered right up until the moment of its death.

There were small tunnels leading out from the main cavern where I’d been attacked by that invisible creature, almost all of them too narrow to allow it to escape. It seemed to have been primarily subsisting on nothing but mana and the occasional sand worm when it felt like digging through the sand pits at the very end of the tunnel I’d been exploring before I discovered the gestalt.

I ignored that route myself, since it wasn’t really any faster to dig through sand with transmutation than it was to go through solid rock. It probably wasn’t a coincidence that the closest spot to the moon core was actually the gestalt’s home, which worked well for me since it cut down on the backtracking I needed to do.

Two miles of dirt, stone, and sand were all that separated me from my goal. A few hours of work would see me there, probably with an extra hour or more to deal with interference from any curious and hungry sand worms that happened to be in the area. As long as Ammun’s forces didn’t pick today to make their move, I could finish this job up.

I started digging at the same steady and careful pace I always used, a few feet at a time as I chained transmutation spells one after another after another. After about ten minutes, I made it to the outside edge of the rock layer and pushed back into sand, where things began to slow down both because of my need to ensure I'd properly reinforced the tunnel and because all the mana I'd been spending had apparently drawn in a crowd.

No less than six different sand worms, all of them big enough to swallow me whole, attacked me within a few minutes of burrowing out into their territory. Fortunately, all of them had enough mana that it was easy to feel their approach and ready myself. I even went so far as to butcher the corpses and stuff them into the spatial box in my pocket. Hopefully, it would soothe some of Grandfather’s ruffled feathers.

After the first hour of digging and fighting, I took a break to consult the mental map the gestalt had given me to determine if I needed to make any adjustments. Everything seemed to be on course, but without being able to scry through a mile of sand, I had no way to know for sure. The best I could do was keep digging and hope nothing went wrong.

By the end of the second hour, I was pleased to find that I could feel subtle pulses of mana up ahead. Those only got stronger as I dug, and I took the fact that I’d fended off several dozen massive sand worms as a good sign. I started stretching earth sense ahead of me, hoping to pick up the moon core on a sweep. It would be incredibly easy to tunnel right past it, missing it by a hundred feet or less.

Then, finally, my divinations found something. Or rather, earth sense picked up a hole in the ground. It didn’t make sense, either. There was nothing but sand around it, no supporting structures inside the void and no rock shell to explain the absence of material. There was plenty of mana, presumably from the moon core itself, but I didn’t sense any sort of active spell.

The void shifted, pushing the walls of sand back a foot before settling back into place. Sand poured down from above, filling the empty space within seconds.

“That’s impossible,” I said aloud.

Earth sense wasn’t going to cut it here, and normal scrying would struggle to pierce walls thicker than a foot or two, but if the void was what I thought it was, I had other options. A quick spell later confirmed my fears. The void was a creature buried underground, a creature so absolutely massive that I couldn’t even get the whole of its shape.

Could a sand worm live and grow indefinitely, given a big enough source of mana? How large would one be if it had a thousand years of exposure to something like a fragment of moon core? And, most importantly, how difficult would it be to take that moon core away? It would be a death sentence for a monster so massive that it couldn’t live without an unlimited mana budget.

The last layer of sand fell away before my eyes, revealing a leathery brown wall. If I hadn’t already figured out what I was seeing, I’d never have guessed I was looking at the monster’s body. I could feel the mana from the massive worm radiating out, so heavy that I wasn’t even sure there was a moon core somewhere past it.

Maybe I could dig around the worm and come at the moon core from another angle, but I had a suspicion that it was wrapped entirely around the stone. No matter which direction I approached from, I’d have a guardian monster to deal with. To that end, I needed to get some space to fight in, otherwise I was liable to be smeared across the sand the first time it shifted.

A case of theft: this story is not rightfully on Amazon; if you spot it, report the violation.

If there was ever a time to put a master-tier transmutation called abyssal maw to good use, this was it. The problem was that I wasn’t sure the chasm it ripped open would be big enough. Also, it was entirely likely that if I used the spell down here, it would cause the roof of the newly opened pit to pour down and crush me.

What I needed was a combination of spells to keep me safe while dislodging the worm from around the moon core so that I could steal it. And if that didn’t work, killing it was an acceptable alternative. A plan started to come together in my head, one that I spent a few minutes turning around to look at from every angle.

Once I was confident that it would work, I set about pulling it off.

* * *

The trickiest part of the abyssal maw spell was that it was designed to split the ground open directly underneath me. Casting it out in front of me required some off-the-cuff modifications, always a tricky proposition when dealing with spells at this level of complexity. The spell went off without a hitch, however, and a chasm ripped open beneath the worm’s body as sand was transmuted into air and—on the outer edges—stone.

As I’d suspected, the worm’s bulk was so massive that even with that spell, it barely budged. What the spell did do was get the monster’s attention. Thankfully, there was so much mana permeating the area that it couldn’t sense me. I’d used elemental form to shift myself into an earth elemental, which wasn’t generally all that useful since earth wasn’t really known for moving, so the spell more or less locked me into one position.

But it made me indistinguishable from the rest of the sand around here, and that was the important part. Other than by sensing the mana from the spells I was casting, it was practically impossible to find me.

Core rupture was the next step in my plan. Every living creature, whether it was a fifty-ton worm or a single transparent ant, had a mana core, and in this case, the worm had the largest one I’d ever encountered. I wasn’t sure a single core rupture would actually slow it down, not in the short-term.

Unfortunately for the worm, I was well past the point where I had to worry about conserving my mana. I had enough in my body alone to cast all the master-tier spells I needed, not even considering my mana crystal, which held easily fifty times as much mana as I was capable of.

Another thing about core rupture: it was a combat spell, which meant it was designed to be cast quickly. Three of them hit the sand worm in the space of a second, and if abyssal maw woke it up, having its core carved up got it moving.

The ground started vibrating as it thrashed in agony, mana bleeding from it in explosive bursts. I drank in what I could, but even at stage six, my mana core simply couldn’t pull mana from the environment at the speed the worm was losing it.

A coil of the worm’s body swept through the sand that made up my elemental form, scattering me across a span of twenty feet or so. It wasn’t an attack so much as random flailing, but it dislodged the monster and caused part of its body to slip into the open abyssal maw beneath it. That was all it took to start the chain reaction, and soon the entire worm was slipping out of place. Unfortunately, that wasn’t enough to make it let go of the moon core it had wrapped itself around, and that fell a thousand feet with it. Fresh sand poured down on top of us, reburying the monster in place.

I could only imagine what the surface looked like right now. We were so far down that it was possible it was undisturbed, but I doubted it. Between the worm crashing against the sand, sending vibrations rolling through it, and the sudden loss of tons and tons of earth, there had to be some sign of something going on.

If there hadn’t been already, there definitely would be in the next few minutes. I cast a second abyssal maw, this time directly above the worm. The new void immediately started filling in with sand, literally dumping an incalculable amount of weight down on the monster.

Burrowing through sand was one thing, but giving it a thousand feet to fall before it slammed down on top of a living creature was something else. Honestly, I wasn’t confident that even this would seriously be enough to injure it, but it was my first backup plan if the drop didn’t cause the monster to lose its grip on the moon core.

I learned two things at that point. First: the worm wasn’t too big to shrug off getting slammed with that kind of weight. Second: it was big enough to fight through it. I was essentially fighting blind underground with only extremely limited scrying to show me anything at all, but earth sense told me the behemoth was starting to uncoil its body and lunging straight up, no doubt hunting whatever had attacked it.

As an earth elemental, there was practically no way I could be injured. Even if the worm scattered the motes of sand that made up my current body, I’d just pull my consciousness back together into a unified whole again. So I wasn’t particularly concerned about being killed right now so much as I was that the worm would wriggle its way through a few miles of sand, necessitating I track it down and start the fight all over again.

I needn’t have worried. It went straight up, its body so massive that when the part near me I could actually sense began moving, I was pulled up along with it. I spared a moment to consider what exactly was on the surface above me and hoped we weren’t about to come up directly beneath some poor farming village on the outskirts of Derro, but it was a passing concern. The odds were astronomically low, anyway.

The worm surged upward, still carrying the moon core along with it, as it searched for its unknown assailant. What had taken me hours and hours of digging took it no more than a minute before it breached the surface and kept rising, a thousand feet straight into the air. That was when I was thrown free of the ground as part of a continuous geyser of sand.

Fresh scrying spells flashed into existence as I finally got my first good look at this thing. It was at least two hundred feet thick and already a quarter mile into the sky with an unknown portion of its body still underground supporting it. Despite the damage I’d done to it, it hardly looked hurt at all.

Well then, I’d just have to do a whole lot more.