Darkmantle - Dungeons on Automatic Bestiary

Magical Beast · SM -1 Darkmantle [Monster Manual, page 38]

Attributes

ST8

DX10

IQ4

HT11

HP8

Will10

Per10

FP11

Basic Speed5.25

Basic Move1

Dodge8

DR2

Melee attacks

Usage	Level	Damage	Reach
Sharp TeethSharp Teeth (12): thrust 1d-3 cutting (KYOS: 1d-4 cutting), Reach C.	12	thrust 1d-3 cutting (KYOS: 1d-4 cutting)	C
Sharp ClawsSharp Claws (12): thrust 1d-3 cutting (KYOS: 1d-4 cutting), Reach C.	12	thrust 1d-3 cutting (KYOS: 1d-4 cutting)	C
GrappleGrapple (26): The tentacles are not very strong, but the darkmantle has many of them. Wrestling at DX+2 gives the cloaker a ST score of 10 for the purpose of grappling. Usually it drops from the ceiling, grabs the head, and then employs Constriction Attack. Effective skill 26 includes a +14 bonus for using 8 arms at once.	26	The tentacles are not very strong, but the darkmantle has many of them. Wrestling at DX+2 gives the cloaker a ST score of 10 for the purpose of grappling. Usually it drops from the ceiling, grabs the head, and then employs Constriction Attack. Effective skill 26 includes a +14 bonus for using 8 arms at once	—
DarknessDarkness (12): The darkmantle may fill a two-yard-radius area with darkness. No one can see into the affected area, and no one within the affected area can see anything; see p. B394 for combat rules. The Dark Vision advantage lets you see through this effect, but Night Vision and Infravision. To place the area at a distance, use Innate Attack (Gaze), with normal range penalties, but at +4 for affecting an area.	12	The darkmantle may fill a two-yard-radius area with darkness. No one can see into the affected area, and no one within the affected area can see anything; see p. B394 for combat rules. The Dark Vision advantage lets you see through this effect, but Night Vision and Infravision. To place the area at a distance, use Innate Attack (Gaze), with normal range penalties, but at +4 for affecting an area	—

Traits (19)

Blindness
Chameleon 3
Clinging (Temporary Disadvantage, No Legs (Sessile))
Detect Light (Precise)
Double-Jointed
Flight (Magical; Slow)
Good Grip 2
Horizontal
Injury Tolerance (No Head, No Neck)
Invertebrate
Metabolism Control 6 (Hibernation)
No Fine Manipulators
No Legs (Slithers)
Perfect Balance
Reduced Consumption 3 (Food Only)
Restricted Diet (Carnivore)
Short Lifespan 3
Sonar (Accessibility, Not in water)
Wild Animal

Skills (5)

12Brawling
14Camouflage
12Innate Attack (Gaze)
14Stealth
12Wrestling

Notes

GCS ancestry draft: gcs/darkmantle.gct
Source template total: 32 points.
Library-rebuilt template total: 32 points.
CER was computed from parsed Typical Stats using the Dungeons On Automatic baseline CER path.
Review attacks, special abilities, encounter frequency, treasure, grappling, and GCS modifiers before approval.

Encounter rating

CER13

Offense12

Protection1

Threat tierminor

Appearing6

Wandering4

GCS v5 downloads

Where this one came from

Source record: Darkmantle [Monster Manual, page 38]
Source system: gurps_4e_fan_conversion / author_permission
Released under: cc_by_4_0
Conversion: 0.2.0-reviewed
Review status: approved
Credit: Original GURPS conversion by Enraged Eggplant, from Monsters (May 11, 2024); adapted and republished with permission.

GCS ancestry draft: gcs/darkmantle.gct
Source template total: 32 points.
Library-rebuilt template total: 32 points.
CER was computed from parsed Typical Stats using the Dungeons On Automatic baseline CER path.
CER recomputed from the reviewed Typical Stats through the canonical Dungeons on Automatic CER path: OR 12, PR 1, CER 13, threat tier minor.
Encounter metadata derived (gregarious): average number appearing 6, wandering weight 4. Encounter metadata derived for 0.2.0 from the reviewed threat tier and creature class (appearing: minor 4 / standard 2 / major 1 / severe 1, forced to 1 for solitary classes — including swarms, which are a single multi-body creature — and raised to 6 for gregarious minor creatures; wandering weight: minor 4 / standard 3 / major 2 / severe 1). The fan-conversion source states no appearing-in-numbers or wandering values, so these are derived, not source mechanics.
Lair, treasure, and grappling remain unpopulated in 0.2.0 by package policy: the authorized fan-conversion source states no lair, treasure, or grappling values, and review declines to invent them. See review/policy/0.2.0-empty-field-policy.md.
Review approved by automated-mechanical-review on 2026-07-26 (batch ee-2026-07-26-b4-special-mechanics); GCS fidelity check passed, DOA playability check passed.
Special-mechanics record. Mechanics the CER path cannot price are named per record in review/reports/cer-audit.md rather than folded into the number, and encounter counts are capped where a save-or-disable attack is present.

Enraged Eggplant GURPS monster conversions; used, adapted, and republished with unrestricted permission from the author. Portrait and tokens are AI-generated original art. Sources and credits.