Station mimics are six enormous predatory bosses concealed within the stations of the Iron Tangle, the fourth floor of the dungeon. A station can function as a transit stop until passengers enter the creature's reach; its apparent architecture then becomes a mouth, tongue, and source of mobile minions. One of the six, the city boss at station 433, attacks Bautista's group, is accidentally transported to trainyard E by Carl's portal cart, and is eventually identified as a level 90 Mimic Rex. Its movements turn a dangerous station into a threat to crawlers across the trainyard.
The trap at station 433
Madison, an Iron Tangle employee who describes herself as benefits manager for the six station mimics, calls them ravenous and says workers are instructed to direct customers off the train at station 433. Her explanation makes the station's purpose clear before Carl sees it: the transit system delivers passengers to a predator under the guise of an ordinary stop. She gives Carl a count of six, but offers no warning that would help a passenger recognize one from the platform. Carl immediately messages Bautista not to leave the train at the terminus.
The warning reaches Bautista too late. His group has gathered roughly 400 crawlers on a train. When the first people go up the station stairs, the station swallows about twenty of them. The remaining crawlers fight on the platform while a tongue reaches for them and walking mouths emerge from the boss. Bautista reports that the minions are too strong for his party and that they are waiting for another train to escape. Some members of the group have sold their protective hats, complicating the routes available to them. This is a mass casualty attack rather than an encounter with a monster occupying one room: the very stairway the group expects to use is part of the danger.
Carl relays what he learns from Madison to Bautista and later sends a wider warning about the mimics at station 433. Bautista and the survivors withdraw to a train that is still running. Their retreat preserves a way out of the immediate attack, but it does not defeat the boss or make the station safe. The episode establishes why information about the station matters as much as fighting strength. Passengers who follow the normal flow from train to platform to stairs can enter the creature before they know a battle has begun.
A boss that changes the shape of a station
The station mimic does more than wait for prey inside its disguise. Its tongue can reach onto the platform, and it expels separate creatures to pursue crawlers. When Bautista later describes fighting it, he says severed portions grow legs and return to the main mass. Blunt weapons have proved ineffective against it, and it resists magic. His assessment is that only an exceptionally large explosion might work, although he has no tested way to kill it. These are the observations of a survivor, not a complete inventory of the species' abilities.
Elle obtains a more specific warning from her manager after Carl asks whether there is a way to destroy a giant mimic. Small mimics can be killed if identified, but a giant one is a different problem. According to the manager, removing more than half its mass at once stops the main body from healing or changing shape and leaves it vulnerable. The detached pieces then attack independently and die only when the parent dies. The advice explains why ordinary cutting attacks are counterproductive: a small severed part can return, while a sufficiently large separation creates a new danger at the same moment it weakens the boss. Carl receives this information after the station 433 mimic has already escaped its original position.
The creature's camouflage is flexible enough to extend beyond a whole station. When Carl, Donut, and Katia approach station 433 in an interdiction cart fitted with a portal, a red and white railroad crossing barrier appears across the tracks. The tracks beyond it look clear. Carl recognizes the obstacle as a trap only after a brief delay, when he sees a fleshy connection leading from the barrier back into the station. The cart strikes the false barrier, and its portal draws in the entire city boss. The mimic's projection onto the track defeats the assumption that keeping to a moving train is enough to avoid contact with it.
Relocation to trainyard E
The cart's portal deposits the station 433 mimic in trainyard E. The transfer removes the immediate threat from its original platform, but creates another hazard at a crowded junction. Carl and his companions have also sent crawlers to the yard, and he fears the creature may reach them. When he checks the portal's view, the mimic occupies a large part of the cavern: a shapeless mass as large as a neighborhood block, reaching toward the ceiling and appearing to swallow half a station. Carl is struck by how much larger it is than the station he had expected it to imitate.
The creature soon begins taking the form of an oversized Iron Tangle administrative building. Its first floor becomes a vast mouth with person-sized teeth, and a tongue extends from it toward the tracks. This new disguise is built from the mimic's own mass in an environment where a real administrative building also exists. Its relocation therefore does not turn it into a stationary object stranded away from home. It can occupy the trainyard, adopt a local structure's shape, and continue hunting.
Bautista, reunited with Carl after the transfer, is alarmed that the group might have to confront the same boss again. Carl instead closes the portal leading to trainyard E and takes the gathered survivors through a different portal toward yard H. Hats allow them to use that route. The decision avoids marching the group into a creature that now expects traffic through the trainyard portal. Carl's intervention saves Bautista's people from a second immediate encounter, but leaves the mimic alive where other crawlers still need to travel.
Its presence may also conceal an exit. After the mimic leaves station 433, Carl sees an indication on the map that he thinks could be a stairwell at that station. He compares the possibility with an earlier case in which a city boss obscured a stairwell. He explicitly treats this as a guess rather than a confirmed exit. The point matters to the mimic's role on the floor: the boss can obstruct access to a location that might otherwise offer a route down, while the search for a usable stairwell continues under time pressure.
Six mimics and the Tangle's layout
Katia repeatedly questions Madison's figure of six. The number seems too small for the scale and apparent repetition of the Iron Tangle's stations. After Carl and the others assemble more of the transit map, Mordecai recognizes its named lines as a simplified representation of old galactic routes. He identifies the six station mimics as part of that design: according to his account of early Syndicate history, the H'lene maintained six deceptive waystations near the center of the network, robbed and ate travelers, and took their technology. The historical H'lene waystations were not literal mimics, although they are represented that way. The floor's bosses therefore dramatize a particular story behind the map rather than merely adding six unrelated monsters to it.
Katia's proposed solution to the numerical puzzle is that each mimic occupies two stations at once. She folds and rearranges her map, then argues that the tracks have another side, possibly inverted beneath the side the crawlers can see. If two station faces belong to the same structure, six very large creatures could account for more apparent mimic stations than a single visible map suggests. Mordecai confirms that the dungeon can invert spaces, but Katia presents the detailed track arrangement as her reconstruction, not as something she has physically inspected. Her theory also explains why the transferred mimic has much more mass than Carl expected from looking at one station.
This interpretation does not make the bosses harmless once one station face is avoided. It instead links their unusual size to the geometry of the floor and warns that a crawler's visible route may be only one side of a larger transit system. Katia continues to count five mimics still to be dealt with after the station 433 boss is moved. The six-boss count remains important both to the map puzzle and to the practical risk of treating other stations as secure merely because one has been cleared.
The trainyard crisis
When the floor enters its final crisis, the mimic at trainyard E becomes part of a wider breakdown of safe routes. Carl receives a report of crawlers trapped between the yard and monsters emerging from the tunnels. They attempt to reach the employee line but cannot get close enough. The mimic sends pieces of itself after them from behind, so retreat from one threat exposes them to another. Other groups that stayed in stations have suffered heavy losses, while groups that fell back cannot necessarily reenter. The boss's range and ability to detach attackers make the yard especially difficult to cross during a general evacuation.
Carl later approaches the area with an interdiction cart and a small group. From a distance, he sees the mimic looming as high as the chamber, only partly maintaining its building disguise. Its red eyes are visible above the yard. Reports tell him that its long tongue and minions are attacking people throughout the area. Crawlers have taken shelter in a burnt administrative building and in a train car, with ghouls and the mimic's mobile mouths between them and safety. The mouths are large, legged creatures; dividing one can produce two attackers. The boss is no longer simply the hidden danger at the top of station stairs. It now controls space around stranded groups, complicating rescue even for crawlers who know exactly what it is.
Carl considers using the portal cart to move the mimic again, but the open yard removes the tunnel's protection. The creature could reach the team from the side or above before they could position the cart. That constraint shapes his next plan. He means to summon the war god Grull into the yard to kill the mimic, switch the portal toward the abyss, and use a second summoning to pull the god away before he can attack the crawlers. The plan depends on precise timing and on Grull choosing the mimic as his immediate target.
Death of the Mimic Rex
The attempt goes wrong when Carl himself falls through the portal into trainyard E with the summoning victim. A dungeon presentation identifies the creature facing him as a level 90 Mimic Rex, a city boss, and attributes more than 23,000 crawler deaths to it at that point. That count belongs to this named boss in the floor's announcement; it is not a count for all six station mimics. The boss lashes its train-sized tongue at Carl as Grull forms, then releases a swarm of its mouth minions. One is identified as a level 35 Jabbering Jibber-Jabber, a Mimic Rex minion that can split into smaller versions when killed.
Grull's arrival does not make the yard safe for Carl. The god is pursuing him, and the mimic occupies the space between them. Carl uses invisibility and moves among the trains while a mouth minion blocks his path. He gets an explosive into that minion's mouth and escapes the blast. Grull then strikes through the Mimic Rex with his axe, splitting its huge body in two. The remaining minions react to the death of their parent and turn on the god. The kill comes from an overwhelming attack by Grull rather than from Bautista's untested proposal to blast the boss or from Carl's group slowly wearing it down.
Afterward, the dead mimic leaves a massive pile of remains in the trainyard. Carl finds the Map of the Stars in them. The reward adds boss locations and descriptions across a large region to his map, although he receives it late in the floor's ordeal. The death is also followed by additional ghoul generators exploding; Carl separately hears of more generators failing after the Maestro is sent into the abyss and treats the precise cause of those later failures as uncertain. The named city boss at station 433 is dead, but the earlier count of six applies to the floor as a whole. Nothing in this encounter establishes that all the other station mimics were defeated with it.