Everyone who's ever delved in a dungeon knows treasure chest mimics (Mendax arca). They're the most common and successful species of mimic in the dungeon ecosystem thanks to their highly effective bait, but the average dungeon is home to other, rarer species of mimic as well.
Architectural mimics inhabit dungeons alongside their flashier cousins and often go unnoticed due to their excellent camouflage. Their stealth and the wide variety in their hunting methods make them much more dangerous than sessile Chest Mimics. They're faster, more tenacious, and much more intelligent; often choosing specific targets instead of blindly attacking the first prey to wander close. Species in the architectural genus also regularly cooperate, living in mutualistic and commensal symbiosis with each other and other dungeon fauna and, in the case of Statue Mimics, hunting in packs.
While the odds of encountering one of these fascinating creatures is low, it's wise to keep a careful eye on your surroundings. Anything you see could be a mimic lying in wait.
All mimics require a:
DC 17 DEX save to avoid their initial ambush/getting grabbed
DC 16 STR check to break free once grabbed/entangled
DC 15 CON save to resist their venoms/toxins
1 Brick (Calumnia elidocaput)
Replace individual bricks and masonry elements in walls and ceilings. When prey passes below they leap down aiming for the head. Sometimes they live in floors and cause falls by shifting violently underfoot, but prefer a gravity-assisted ambush. Exactly as heavy as a brick. (1d12 damage)
2 Beams (Calumnia destructans)
Replace load-bearing structures like trusses and support pillars, then use their own weight as well as the collapsing rubble to crush prey. (3d12 damage)
3 Pillar (Calumnia incingodes)
Wraps itself around existing pillars in a thick skin that looks like carved stone. Occasionally have spots of faux cut gems and precious metals to make themselves even more alluring. When prey comes to examine the carvings it peels away from the column and falls, pinning the prey under a suffocating sheet of muscle. (1d8 damage/turn)
4 Arch (Calumnia fornixae)
Lines the inner surface of existing arches and exudes fine, nearly invisible threads coated with cnidocysts. Crawls down to devour paralyzed prey after they walk through its web. (1 CON damage, save or be paralyzed for 6 turns)
5 Door (Calumnia portico)
Embeds itself in walls leaving only its jaw-panel and lip-jambs visible. When prey opens its jaw it strikes with sets of inner pharengeal jaws to grab and draw them in. (3d6 damage/turn)
6 Trapdoor (Calumnia operculata)
Embeds itself mouth-up in the floor and waits for prey to investigate. The jaw looks like a concealed hatch and the first 10' of its esophagus resembles a stone shaft with a sturdy ladder. Snaps its mouth shut and starts chewing once prey is fully inside. (2d6 damage/turn)
7 Flooring (Calumnia tenax)
A communal species that replaces sections of planks, tiles, stones, and other joined floor materials. They secrete a sticky, numbing mucus that traps and slowly digests prey. (DEX save to not fall over, CON save to resist going numb, STR save to break free)
8 Mosaic (Confictura tessellatus)
Adheres to floors, walls, and ceilings. Lays dormant until it senses heat, then leaps off the surface it's on to engulf the prey and grind them to paste with its sharp radula-like tiles. (1d10 damage/round)
9 Stairs (Calumnia vorago)
Graft themselves between floors and hibernate until prey climbs on them. When they sense weight they open their mouths, retracting pseudo-step teeth to drop prey into their waiting stomach. They prefer large meals and rarely eat individual prey, targeting groups of two or three instead. The weight threshold needed to attract their attention is high. (2d12 damage/turn, STR save to climb out)
10 Railing (Calumnia cancelli)
Replaces banisters, safety rails, and low walls. They prefer locations near sheer drops, the more precipitous the better, but can be found anywhere. They lay dormant until prey leans on them. When they sense weight their either give way so the prey falls to their death, or entangle limbs and inject a paralytic venom depending on the subspecies. (Save or 1d20+5 fall damage) OR (Save or be paralyzed, 1d4 damage/turn)
11 Pipes (Calumnia fistulata)
Insinuate themselves in the plumbing of a building. They passively carry whatever the system transports until they sense prey, then spray their contents in a surprise attack. Capable of withstanding extreme temperatures, pressure, and corrosives. Occasionally replace sinks with mouths. (Save or be drenched in and damaged by pipe contents)
12 Gutter (Calumnia fistulata canalis)
Related to Pipe Mimics and sometimes thought to be a larval instar. They attach to the edges of roofs and embed near walkways, collecting runoff and mixing it with digestive juices to produce a rank slurry they spray on passing prey. (1d12 acid damage)
13 Sewer (Fictus cloacarius)
Giant wormlike mimics that burrow under cities. Their guts resemble spacious stone masonry tunnels and can actually function as sewers. They rely on the sewer ecosystem they host for sustenance and aren't particularly interested in individual adventurers. It's uncertain if they even notice a single humanoid's presence at all. When seriously irritated or injured they can contract their passages and crush everything inside. (Contracts if it takes 100 damage at once, 300 in an hour, 1000 in a day, or 3000 in a month.)
14 Fountain (Fictus immergo)
Plants itself near a source of running water to fill its basin. It's an opportunistic feeder and mostly relies on the insects, birds, and small animals that are drawn by an open pool of water, but will eagerly snare and drown larger prey. (Save to break free or drown in 6 rounds)
15 Window (Calumnia prospectans)
Embed themselves in walls and display high-resolution decoy images of an outside world using a sophisticated combination of chromatophores and bioluminescence. When prey tries to look through or open them they spring off the wall and engulf it in a sticky, membranous digestive sac. (Save to break free or suffocate in 3 rounds)
16 Mirror (Confictura indico)
Adhere to walls and doors. They can attack by flinging shards of crystalline exoskeleton but rarely break cover. They hunt cooperatively with other monsters, distracting prey with a false reflection of their surroundings that edits out any threats. Once the other monsters have finished they crawl down to scavenge the remains. (-2 to detecting ambushes and hidden creatures)
17 Light fixture (Confictura lucerae)
Come in a wide variety of forms from grand chandeliers to freestanding floor lamps to tiny sconces and table lamps. They're entirely peaceful decomposers that don't hunt. Easily startled and shy, they light up in alarm when creatures move nearby and flash blindingly when frightened. The can be calmed back to darkness with food. (Roll 3x as many encounters while lit)
18 Wallpaper (Confictura ornata)
Coats the walls of a room in a thin, tough layer of opaque tissue. The skin is porous, providing a habitat for symbiotic molds to grow inside, which produces a distinctive musty smell. When prey comes near it ripples, releasing clouds of toxic spores from its symbionts. (1 WIS damage, save or hallucinate for 6 turns)
19 Soft furnishings (Confictura stragula)
A communal species of threadlike individuals intertwined in soft nest-sheets. Their flexible multicolored bodies let them convincingly reproduce all kinds of textiles, from rugs to curtains to tapestries. When prey touches the nest it unfurls, individuals spooling out to entangle and garrote them. (1d6 damage/turn, save to break free or suffocate in 6 turns)
20 Statue (Confictura effigus)
The most mobile and energetic species of mimic. They hide inside their ornate sculptural exoskeletons and wait for prey to pass by, then begin actively stalking. They're stealthy and prefer to attack from ambush but will run down prey in a high-speed chase if necessary.
Often confused with Living Statues, statue mimics are flesh and blood creatures in shells, not awakened art.
(4HD, 17 AC, 60', 3 attacks/turn (1d10/1d10/1d12+4))
Extra rare!
Treasure (Confictura preciosa)
These small mimics look like individual artifacts and pieces of treasure. They hibernate until they sense heat, then become active and emerge from their shells. Usually the "treasure" portion of their body is an elaborate exoskeleton, but you'll occasionally find them living inside an actual hollow artifact like a hermit crab. They're curious, relatively gentle, and can be interesting pets if fed and cared for properly.