The Core's idea for the 14th-floor entrance was simple: a trap in the form of a fall hidden under sand.

  It had already set an exit that was a trap before in the form of the Mimic door on the 6th floor, although The Core didn't really count it, as the exit was completely normal; you just had to kill a monster that just happened to look exactly like the floor's exit to go through it!

  This meant this was going to be its first actual exit trap, which is why it was both excited and nervous about implementing it.

  Excited because it was improving its dungeon in ways never seen before, at least in its halls.

  Nervous because it didn't know exactly how it would do so.

  That was because it had never made traps before. If you looked at its dungeon, you'd notice a chronic lack of traps and puzzles.

  Why is that when dungeons are known not only for their hazardous terrain and dangerous monsters but also for disastrous traps? There was a reason a ranger was counted as one of the must-haves in a standard five-person adventure team.

  The explanation was very simple: most traps and puzzles a Core had to make and think of by itself. With the few exceptions of the base traps that the manual shows you as examples, such as the Mana Overload and pitfall traps, everything related to them is in a Dungeon Core's metaphorical hands.

  For someone like The Core, this meant disaster. It only attempted making some at the beginning of its life, but when it came to the conclusion that no invaders would ever set foot in its dungeon, it stopped bothering and instead redesigned its halls over and over again.

  This led to it not developing any skills in that regard, and as such, The Core didn't even think of including any when it was remaking its dungeon in a hurry to be ready for invaders.

  However, now that it had the time, space, and invaders who were coming into its halls, it wanted to try.

  The Core went to work; first, it picked a suitable spot to make the trap, and then it looked underneath the sand layer and began to dig through the rock placed there.

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  As there was sand at the top and it didn't want its progress to be ruined along with the 13th floor's looks by having a certain amount of sand lowered in a perfect circle, since there was no wind to scatter it, it engraved runes to stop the sand from falling first.

  It didn't know exactly how far it should dig; it only had a vague idea about how it was going to look, after all. Which didn't make this plan seem promising, but that wouldn't deter it.

  When The Core decided the tunnel was long enough, it stopped digging and went back to the entrance.

  Now came the hard part of figuring out how to make the sand collapse on itself in order to reveal the entrance to the 14th floor.

  In the basic traps given as examples in the manual, there was a fall trap, which used runes engraved on solid surfaces, usually the ground, to unmake the material between the runes.

  It, however, couldn't be used without modifications, considering that sand wasn't counted as solid ground.

  However, even if the Core did modify the runes a bit, it would still be a hard task to accomplish as the small size of sand grains posed a significant challenge in rune engraving, not to mention their sheer numbers. Doing it this way would be simply too much of a time and energy-consuming affair to be cost-effective.

  The Core was certain there must be a trick to this process; it just needed to figure it out.

  Maybe if it made a thin sheet of sandstone to hide between the sand to use as the foundation for making runes?

  It didn't need it to stick out to the surface; the thin layer of sand that would be left behind wouldn't obstruct an invader's fall.

  And so The Core tried the method it just thought of, creating a wall using sandstone while making sure that it wouldn't be visible.

  It ended it much sooner than it thought it would, but it just didn't want to risk an invader figuring something out.

  It was its first trap that an invader would encounter; it couldn't fail!

  The Core was aware that it could only work properly the first time, as interlopers communicated between themselves and shared information about the dangers of a given dungeon, but that only made its desire for the trap's debut to be grand soar.

  The Core then began engraving the needed runes on the thin sandstone with a slight modification in the form of the trap activating when touched by its signature mana.

  It would remove this once it figured out the trap worked.

  When it finished making the runes, it activated the trap with excitement.

  The sand between the sandstone unmade itself, and the sand not between it also unmade itself once it entered the range of the runes, showcasing the deep hole.

  The trap was successful!

  The Core cheered as it looked upon its creation. Not wasting any second, it quickly removed the added modification, deactivated the runes, and filled the hole back up with sand.

  Now it could make the 14th floor with its mind at ease.