The ground erupts. Thirty feet of gray worm-body rises from the soil, and the mouth — far too large for its body — is already open. The last thing you want is to be closest to it.
Core Statistics #
| Stat | Value |
|---|---|
| Hit Dice | 6d8* (avg 27 HP) |
| AC | 14 |
| AV | 2 (melee) / 1 (missile) |
| HR | +5 |
| FR | +4 |
| FD | 14 |
| Move | 60 ft (20 ft encounter) — surface; 30 ft (10 ft encounter) — burrowing |
| Attacks | 1 bite: 1d8 + swallow-whole on 19–20 |
| No. Appearing | 1d3 (1d3) |
| Save As | Fighter 3 |
| Morale | 9 |
| Treasure | Type B |
| Alignment | Neutral |
| CR | 6 |
| Size | Large (30 ft long) |
| Intelligence | None (INT 0) |
| XP | 500 |
AC/AV Reasoning #
RC original is AC 6 (descending) = Ascending AC 14. The caecilia is a giant limbless worm creature — its protection is its rubbery thick skin and the difficulty of striking something that moves like liquid.
- AC 14 — A 30-foot worm presents an unusual attack profile. It has no limbs, no joints, no standing posture — it moves in continuous curves and its cross-section is roughly circular. Striking it cleanly requires aiming at a constantly shifting cylindrical surface. AC 14 reflects this genuine targeting difficulty
- AV 2 (melee) — The caecilia’s skin is thick, rubbery, and somewhat resistant to cutting and piercing weapons. Blunt weapons deal full damage; slashing weapons partially deflect off the curved surface. AV 2 is modest but consistent — appropriate for a creature whose primary defense is being hard to hit rather than hard to injure
- AV 1 (missile) — Arrows penetrate the rubbery skin readily but may not reach vital organs in a 30-foot worm with no clear vulnerable zone. Still, missile fire is slightly more effective than melee against the curved surface
Skill Slots (5 total — 6 HD = 4 base; asterisk = 1 special ability) #
6 HD falls in the 1–8 HD tier = 4 base slots + 1 asterisk = 5 total. INT 0 caps useful development.
| Slot | Skill / Ability | Notes |
|---|---|---|
| 1 | HR Investment (Basic) | HR +5; the bite is the caecilia’s entire offense — a massive tooth-lined maw at the end of a 30-foot muscular body. The HR reflects both the size of the mouth (hard to avoid once it lunges) and the targeting precision developed through ambush predation |
| 2 | Swallow Whole (innate, special) | Unadjusted roll of 19 or 20 triggers swallow. Full mechanics below. The asterisk |
| 3 | Burrow Ambush (innate) | Lies in wait in loose soil just below the surface. Cannot be detected by sight (the ground appears undisturbed). Detection requires Alertness (DEX check at difficulty –3 in open terrain, –5 in areas of disturbed soil) or Danger Sense. When the ambush triggers, treat as surprise (1–4 on d6 — the caecilia surges up with explosive suddenness). Full mechanics below |
| 4 | Alertness (Basic) | Detects surface movement through vibration sensing — any creature walking on the surface above it is detected at 60 ft range. The caecilia “shoots up” precisely when prey is positioned optimally. It does not breach until prey is directly overhead or within 5 ft |
| 5 | Endurance (Basic) | Continues fighting at full capacity until dead — Morale 9 means it is committed but will abandon prey if severely damaged. Once a creature is swallowed it fights with total commitment (the swallowing process is one-way — releasing prey requires intent the caecilia cannot form, only death or killing the caecilia releases the swallowed victim) |
Martial Style #
Style: Control (Basic rank) — The Warden, applied to the swallow mechanic Rank: Basic
The caecilia does not deal damage through speed or precision — it deals damage through engulfment. The bite is a delivery mechanism for the swallow. The Control style’s emphasis on restraining and containing the target is precisely correct for a creature whose winning condition is “target is inside me.”
No Combat Breath: INT 0, pure predatory instinct. Does not Winden or Exhaust.
Burrow Ambush — Complete Mechanics #
Setup #
The caecilia lies in loose soil at a depth of 1–3 ft below the surface. The ground above it appears undisturbed — the caecilia’s long flexible body displaces soil without obvious mounding when it settles in position.
Detection:
- Visual inspection: The ground looks normal. No detection possible by sight unless the party is actively probing the soil (a character stabbing the ground with a spear every 5 ft — tedious but effective)
- Alertness (DEX): Check at difficulty –3 in open terrain. Success reveals that the soil has an unusual consistency or slight depression pattern that suggests recent disturbance. Failure reveals nothing
- Danger Sense (WIS): As per the General Skill — detects the threat before it manifests if the check succeeds
- Tremorsense or magical detection: Detect Magic shows nothing (not magical). Locate Animals or equivalent nature magic may detect it. Vibration-sensitive creatures (some dwarves, earth elementals) may notice the caecilia’s position
Breach and Attack #
When prey walks over the caecilia’s position:
Initiative: The caecilia acts in the Maneuver and Missile phase — it surges from the ground as its “movement” and bites in the same action. Characters who are not aware of the threat when it breaches are surprised:
- Surprise roll: 1–4 on d6 (the eruption is fast and from directly below — even alert characters struggle to react in time)
- Surprised characters: Lose DEX bonus to AC for the caecilia’s first bite
The breach: The caecilia shoots upward from the soil, potentially to full height (30 ft of worm surging upward). The sudden appearance of its body parts disturbs nearby terrain — characters adjacent to the breach point but not directly targeted must Save vs. Paralysis or stumble from the ground disturbance (lose their action next round regaining footing — this represents a party caught near a multi-caecilia ambush losing their footing simultaneously).
Multiple caecilia ambush: When 1d3 caecilia are present, each positions itself separately — they are not cooperating intelligently but their separate breach points cover more ground. A party that triggers one caecilia may trigger all of them simultaneously from different positions. Against a party of four, three caecilia breaching simultaneously from three different positions is extremely difficult to manage — each creature attacks its nearest target.
Swallow Whole — Complete Mechanics #
Trigger #
An unadjusted attack roll of 19 or 20 triggers swallowing. This means:
- The raw d20 result must be 19 or 20 — not the modified result
- No bonuses or penalties apply to this check — only the die face matters
- A roll of 19 or 20 that misses the target’s AC still triggers swallowing if the bite connects at all (the RC says “unadjusted attack roll of 19 or 20” — the DM must decide whether the swallow requires the attack to hit normally first, or whether 19-20 automatically hits and swallows regardless of AC. The most consistent reading: the caecilia must still hit the target’s AC, but if the unmodified roll is 19-20, swallowing occurs on a hit)
Probability: 10% chance per attack (19 or 20 on d20). Against a party member the caecilia attacks repeatedly, this produces an average of 1 swallow per 10 rounds of combat. In practice, encounters rarely last 10 rounds — but the threat is always present on every bite.
Swallowed Condition #
The victim:
- Is inside the caecilia’s body — completely enclosed
- Takes 1d8 internal damage per round automatically — no attack roll required
- AV does not apply to internal damage — the crushing digestive process bypasses armor
- Cannot be targeted by outside attackers without risking harming the victim (any attack on the caecilia’s body deals full damage to the caecilia; there is no “precise attack” to extract the victim)
- Can still act but with severe restrictions — see Swallowed Actions below
Duration: The victim takes 1d8 per round “until the victim or the caecilia is dead.” The only ways out are:
- Kill the caecilia — it goes limp and the victim can force their way out (or be extracted) within 1d4 rounds
- The victim dies inside the caecilia
- The caecilia voluntarily releases — impossible, INT 0 means no such decision can be made
Swallowed Actions #
What can a swallowed character do?
Physical attacks: The character can attack the caecilia from inside. They use a light one-handed weapon (dagger, short sword, hand axe) — no two-handed weapons possible in the confined space. The attack is against the caecilia’s interior AC — treat as AC 11 (the interior is soft tissue, easier to damage than the exterior). Damage dealt counts toward killing the caecilia.
Spells: Spells with verbal components are possible (the character can speak, however muffled). Spells with somatic components require DM adjudication — some hand movements are possible in the limited space, others are not. Touch spells can be used against the caecilia’s interior. Area spells centered on the swallowed character affect both the character and the caecilia equally (the character takes their spell’s damage too — Burning Hands in the caecilia’s gut burns both).
Escape attempt: The swallowed character can attempt to force their way out. This requires a Muscle check (STR-based) at difficulty –6 — the caecilia’s muscular walls actively contract. On a success the character has partially worked loose; on two consecutive successes they escape (end up adjacent to the caecilia’s body). This is very difficult without extraordinary STR — most characters depend on their companions killing the caecilia.
Communication: The swallowed character can shout (muffled but audible to adjacent characters) to communicate their situation.
Companions’ Options #
Attack the caecilia: Standard attacks against the body. Every HP reduced brings the caecilia closer to death and release. The urgency is real — the swallowed character is taking 1d8 per round regardless.
Targeted extraction attempt: A character who declares they are cutting toward the swallowed victim (rather than attacking the body generally) makes a Called Shot — HR –4, but on a hit deals damage to the caecilia AND the victim simultaneously (half damage to each from a single cut). This represents trying to cut open the body to extract the victim — risky but direct.
The race: Average 1d8 internal damage = avg 4.5 HP per round. A character with 20 HP has approximately 4–5 rounds before death. Against a caecilia with 27 average HP, companions dealing 5–6 HP/round on average kill it in approximately 5 rounds — close but survivable for a character with reasonable HP.
Post-Death Extraction #
When the caecilia is killed:
- Its muscular walls relax immediately
- The swallowed character can push out in 1 round with a standard STR check (no difficulty modifier — the walls are loose)
- Companions can assist extraction — one person pulling and another pushing from outside = automatic success in 1 round
- The extracted character emerges covered in internal fluids, potentially with minor ongoing burn damage (1d4 HP, save vs. Poison to avoid — the digestive acids are mild, not immediately lethal, but cause irritation)
Habitat & Ecology #
Primary Habitat: Any terrain except Arctic. The RC’s “nearly anywhere” is accurate — loose soil exists in plains, jungle floors, desert sand, forest floors, ruins with compacted earth, and even the upper layers of underground soil. The caecilia selects positions near natural bottlenecks: game trails, dungeon corridors with earthen floors, river fords, and similar locations where prey is channeled.
Diet: Meat-eaters. They consume anything they swallow whole — humanoids, animals, other creatures. The caecilia swallows prey whole and digests over time. The 1d8/round internal damage represents the digestive process beginning immediately.
Group behavior: 1d3 in wilderness or lair. They do not cooperate intelligently (INT 0) but their simultaneous ambush from separate positions creates a dangerous tactical situation. Multiple caecilia in an area have simply converged on the same food-rich location independently.
Detecting territory: Signs of caecilia territory include: irregular soil disturbance patterns (subtle depressions where bodies have recently repositioned), bones and equipment fragments on the surface (remnants of previous victims that were not fully consumed or were passed out), and a notable absence of other burrowing animals (moles, badgers, ground squirrels) who have abandoned the area.
Treasure Type B: The treasure is remnants from partially-consumed victims and the accumulated debris from the caecilia’s feeding area — coins that fell as victims were swallowed, small jewelry that survived digestive processes or was lost before swallowing. The caecilia’s digestive system is not perfect — small metal objects may be passed out rather than consumed.
Encounter Notes #
The ambush setup: The party is moving through terrain with loose soil. Without a successful Alertness or Danger Sense check, they walk into the caecilia’s detection range (60 ft). The caecilia waits until the nearest party member is directly above it, then breaches. The breach is the core drama — everything else follows from whether the party can kill the caecilia before the swallowed character dies.
Identifying caecilia territory: A character with Nature Lore or Survival (both INT-based) can identify the signs described above on a standard check (difficulty –0). This transforms the encounter from “ambush you did not see coming” to “cautious advance through known danger.”
Terrain counter-tactics: Rocky ground, paved roads, stone dungeon floors, and wooden platforms all prevent the burrow ambush — the caecilia cannot position in these surfaces. A party in caecilia territory that stays on stone paths is safe. The RC’s “any except Arctic” habitat means the threat is real almost everywhere, but terrain awareness eliminates it.
Three caecilia simultaneous breach: Against a party of four, three caecilia breaching from three positions while the party is spread out is CR 8 equivalent. Three separate swallow threats, three sets of 1d8/round internal damage counters running simultaneously, each requiring companions to kill that specific caecilia to rescue the victim. This is the hardest version of the encounter.
CR 6 justification:
- 6* HD = CR 6 + 1 (asterisk, swallow whole) = CR 7 theoretical
- Reduced to CR 6: Morale 9 (not suicidal), slow movement (60 ft — can be outmaneuvered after initial breach), INT 0 (no adaptive tactics), single attack per round (only one swallow possible per round)
- Against parties without awareness of the ambush capability: treat as CR 7 — the surprise combined with swallow-whole in the opening round is potentially lethal
