Mimic

Alexy was getting close to the Archivist. Luckily, it wasn't moving too quickly, so despite him limping towards it, he was able to slowly catch up to it. He tried to yell at it, but the creature didn't react at first. At least, until he apparently got close enough as once he yelled that time, the Archivist stopped in one of the brighter areas and slowly started turning towards him. The way it turned looked a little weird, and awkward, but Alexy didn't pay any attention to that. But when he got close to the creature standing in the light, he noticed something was very wrong. It moved its torso in a jerky way, its robe looked more like flesh than a robe, and when he looked at its "face", something he shouldn't do, he didn't feel anything. No dizziness, no headache.
As he made a step backward, the creature split itself in half vertically, and something flew by his head, wounding his nose. Whatever it was, if he stood just a bit closer, he'd probably lose the top of his head right now.
Alexy started to run as quickly as his limping body could.

Creatures of the Dark Halls noticed a long time ago that humans tend to run towards the Archivists in case one of them announces its presence before attacking them. And since dealing with Archivists is almost never worth the trouble or damage they could cause, some of them started adapting in ways that would exploit people's behavior. And so, mimics started showing up.

Appearance

Mimics take on the appearance of Archivists, being an imitation of them made out of flesh. They have a large body resembling the torso of a person in a cape with a growth on top of it that simulates a hollowed-out hood that is completely black inside. Mimics almost always tend to be the size of an average Archivist, about 2.5 meters tall. Their skin is leathery and cold, only sometimes covered with short hair that tends to imitate the fur-covered robes of some Archivists. However, looking up close, it is almost impossible to mistake the two of them. Some of the mimics have patterns on their bodies similar to those of Archivists though compared to some of them, their patterns never glow or change color. They also cannot summon "limbs" but they have their own substitute for them.
Mimics possess multiple eyes located on the main part of their bodies. They can be very simple, only resembling simple dots of color, or can be closer to reptilian or mammalian eyes, with the shapes of their pupils varying between each individual. They can move each eye independently of each other.
Mimics move thanks to hundreds of little tubes underneath their bodies, resembling those of starfishes. The tubes grab onto the surface in front of them pull themselves towards that spot and then push away from it. Similarly to their eyes, the tubes do that independently of each other, creating a smooth but slow movement. Thanks to the adhesiveness of those tubes, they can walk on almost any surface and any prey grabbed onto by them has virtually no chance of escaping.
Mimics possess one giant vertical mouth going through the whole height of their "torso" splitting at the spot where the robe would have its opening. The mouth is filled with teeth and is big and flexible enough that it can easily swallow a whole human standing in front of it. However, should there be problems with capturing their prey by simply ambushing it and jumping at it before it can react, mimics also possess multiple sharp limbs that are usually hidden inside of their mouths that resemble the claws of a mantis that can both be used to extend their reach when grabbing the prey or can wound it thanks to the sharp protrusions on them, decreasing their chance of escape. On average, the mimics have two or four of those claws inside their mouths, though the largest specimen witnessed had twelve. Those claws can be considered their own version of "limbs" and some of them managed to fool people for a few moments longer that they are indeed "limbs".

The differences

There are many similarities between Archivists and mimics though there are things the latter cannot replicate or do it as well.

Archivists

• Tend to move as if they were floating, their robes flow around obstacles or phase through them
• Looking under their hoods causes nausea and nosebleeds
• Patterns on robes can glow or change color, they are sewn into robe
• Can move extremely fast, will react to things happening to the Hall
• React when called from afar
• Can summon "limbs" that take on many different forms

Mimics

• Tend to move clumsily, have to avoid obstacles to not break the illusion of wearing a robe
• No ill effects when looking under their "hoods"
• Patterns on flesh can't glow and are slightly raised
• Can only move slowly, will ignore everything that isn't their prey
• Can't hear when called from afar
• Only have substitute mantis-like claws inside their mouths

Alexy moved as quickly as he could, limping, one foot in front of the other. The creature moved faster than him, but not as fast as real Archivists could. The few times it got close to him, it tried to cut at him again, but a step to the side or a short burst of sprint always let him escape from it. But there was a problem. He was getting tired and the creature didn't seem like letting him go.

Lifespan

Unknown, they more often die from starvation.

Geographic Distribution

• Dark Halls

Habitats

Mimics can show up in any Dark Hall, though they prefer ones where Archivists are already dead and the ones where there is not much light to hide their differences from them for longer.

Growth

Mimics seem to always show up in their adult form though the two of them can be so different from each other, it would be hard to discern which of them is younger or older.

Reproduction

As it is with most creatures of Dark Halls, it is unknown if they reproduce at all and not just get born from the darkness. Mimics tend to be either so territorial or so aggressive towards the Archivists that when two of them meet, they will brutally fight until one of them dies, often leaving the "victor" so wounded, that they won't survive for too long.

Dietary needs

Mimics are obligate carnivores, only being able to digest meat. A few days after eating, they will throw up all of the non-digested parts of their prey, including their clothes, bones, and hair, as big slimy lumps. Mimics require quite a lot of food to survive so they often digest a few things at the same time, so after throwing up, they search those lumps for any meat left on them. They can only survive about two days without eating.

Perception and senses

Compared to most of the creatures of the Dark Halls, mimics tend to have pretty bad eyesight. They can see in the dark, though only at short distances, losing track of their prey if it gets too far unless it carries a light. However, in areas where there are already lights, they can lose what they chase once the distance between them reaches over 20 meters. But while they can't see too far, their multiple eyes guarantee them a full 360-degree vision.
Similarly, to their sight, all of their other senses also seem to be pretty weak, needing them to be close to use them in any effective way. And since they are ambush predators, they don't need them to be strong.