Buy me a coffeeArthropleura
“Arthropleura scuttles through swamps like a living tank, crushing everything in its path!”
Arthropleura’s body consists of 28–32 broad, overlapping tergites adorned with tiny spines and tubercles, forming a defensive carapace over half a meter wide. Beneath each segment lie multiple pairs of jointed legs—around eight pairs per six segments—whose metachronal rhythm produces a smooth, scuttling motion. Its small, bulbous head is tucked under the first tergite, equipped with short, bell-shaped antennae and mandibles suited for shredding plant debris The Sun. The underside features flattened ventral sclerites that anchor powerful musculature, allowing it to bear and propel its massive weight.
Behaviour
Arthropleura prowls slowly but steadily, its synchronized legs pushing it through soft mud and tangled roots without sinking. It ceaselessly forages by following chemical cues detected by its antennae, pausing only to grind and ingest decaying vegetation. Though non-predatory, its mere bulk trampling over undergrowth can inadvertently crush smaller creatures. When sensing danger, it halts and arches its anterior plates skyward, presenting the thickest armor toward threats before reversing into cover.
Habitat
Arthropleura inhabits the humid coal-swamp floodplains these wetlands teem with towering horsetails, clubmosses, and ferns, whose abundant detritus fuels its detritivorous lifestyle. Water-logged soils and fallen logs provide both pathways and shelter, while high atmospheric oxygen levels enable its extraordinary gigantism.
Modus Operandi
- Foraging Trample: Scuttles over leaf litter and root mats, using antennae to locate nutrient-rich detritus.
- Shred and Ingest: Curls its head under the carapace, grinding plant fibers against hardened sclerites before swallowing the pulp.
- Trackway Marking: Leaves distinctive Diplichnites trails—parallel rows of imprints—mapping its routes between feeding and resting sites.
- Defensive Raise: On alarm, elevates its front segments to shield vulnerable parts, then backs away slowly into debris.
Motivation
Arthropleura embodies an evolutionary drive toward maximal detritivory and self-preservation. Its sheer size deters the few terrestrial predators of its era, while its armored exoskeleton and efficient feeding render it the unrivaled decomposer of Carboniferous swamps . In an age of rampant plant growth and scant vertebrate competition, it fulfills a unique ecological niche, recycling massive quantities of organic matter and shaping the very landscape it haunts.
Arthropleura 5e
Arthropleura 3.5
Arthropleura
Large Beast, Unaligned
Armor Class 15 (natural armor)
Hit Points 136 (13d10 + 65)
Speed 20 ft., climb 20 ft.
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 20 (+5) | 8 (−1) | 20 (+5) | 2 (−4) | 12 (+1) | 3 (−4) |
Saving Throws Con +9, Wis +5
Skills Perception +5, Stealth +1 (in thick vegetation)
Damage Resistances bludgeoning, piercing from nonmagical attacks
Senses darkvision 60 ft., tremorsense 30 ft., passive Perception 15
Languages —
Challenge 5 (1,800 XP)
Traits
- Armored Carapace.
Any creature that hits Arthropleura with a melee attack within 5 ft. takes 7 (2d6) piercing damage from its spined plates (recharge 5–6). - Diplichnites Trail.
Arthropleura’s movement leaves a 5 ft-wide, difficult terrain trackway for 1 minute, which can impede or entangle creatures entering it. - Tremorsense.
While in contact with the ground, Arthropleura detects and pinpoint vibrations in the ground up to 30 ft away. - Slow and Steady.
Arthropleura can’t be knocked prone and has advantage on saves to resist being moved or restrained.
Actions
- Multiattack.
Arthropleura makes two attacks: one with its Mandibles and one with its Carapace Slam. - Mandibles. Melee Weapon Attack: +9 to hit, reach 5 ft., one target.
Hit: 19 (3d8 + 5) bludgeoning damage. - Carapace Slam. Melee Weapon Attack: +9 to hit, reach 10 ft., one target.
Hit: 16 (2d10 + 5) bludgeoning damage, and the target is knocked prone. - Groundquake (Recharge 5–6).
Arthropleura pounds the ground. Each creature on the ground within 20 ft. must succeed on a DC 17 Dexterity save or be knocked prone and take 21 (6d6) bludgeoning damage (half as much on success).
Reactions
- Burrowed Retreat.
When reduced to half its hit points or fewer, Arthropleura can burrow into soft earth or mud as a reaction, moving up to 20 ft. and surfacing in an unoccupied space it can see.
Tactics
- Ambush Setup: Uses Tremorsense to detect prey or intruders, then lies in wait beneath leaf litter or shallow water.
- Opening Strike: Initiates combat with Groundquake to knock foes prone, then follows up with Multiattack to maximize damage.
- Defensive Edge: Relies on Armored Carapace to punish melee attackers and Slow and Steady to maintain momentum.
- Tactical Withdrawal: If nearly slain, triggers Burrowed Retreat to disappear into the undergrowth and avoid finishers.
Life reconstruction of Arthropleura armata
Large, black, and built like an invertebrate tank, the giant slips through the undebrush. It would rather run than fight, and thus poses little threat to you or your comnpanions
Originally Posted by Raptorial of the Wizards Community forums.
On this Thread
Arthropleura is a huge 6-foot long millipede that slinks across the swamplands quickly and silently. It specializes in keeping itself from being noticed
| Arthropleura | |
| Medium vermin | |
| Hit Dice | 2d8+8 (17 hp) |
| Initiative | +3 (+3 Dexterity) |
| Speed | 10 ft. (2 squares) |
| Armor Class | 16 (+3 Dexterity, +3 natural), touch 13, flat-footed 13 |
| Base Attack/Grapple | +1/+6 |
| Attack | Bite +6 melee (1d6 +5) |
| Full Attack | Bite +6 melee (1d6 +5) |
| Space/Reach | 5 ft./5 ft. |
| Special Attacks | Constrict |
| Special Qualities | Darkvision 60ft. |
| Saves | Fort +7, Ref +3, Will -3 |
| Abilities | Strength 20, Dexterity 16, Constitution 18, Intelligence 0, Wisdom 4, Charisma 2 |
| Skills | Climb +7, Escape Artist +6, Listen -3, Move Silently +8, Spot -3 |
| Feats | Endurance |
| Environment | Warm swamps |
| Organization | Solitary |
| Challenge Rating | 2 |
| Treasure | None |
| Alignment | Always neutral |
| Advancement | 3-4 HD (Medium); 5-6 HD (Large) |
| Level Adjustment | – |
Combat
Constrict (Ex) A creature with this special attack can crush an opponent, dealing bludgeoning damage, after making a successful grapple check. The amount of damage is given in the creature’s entry. If the creature also has the improved grab ability it deals constriction damage in addition to damage dealt by the weapon used to grab.
vermin possess the following traits.
Mindless No Intelligence score, and immunity to all mind-affecting effects (charms, compulsions, phantasms, patterns, and morale effects).