June 19th, 2017

Alex Riggs

Exotic Encounters Archive

Today is the beginning of Sanctuary Week, and that means that today’s monster is going to be all about protection. Earlier in the year, we presented the ring spirit, and this inspired me to explore another monster that may be of use to PCs, and the first thing that came to mind was a suit of symbiotic armor.



This hideous creature’s elongated, vaguely triangular body is covered in glossy black, insect-like plates of chitin. Beneath, a forest of writhing pink tendrils propel it along the ground. Its head is squat and sleek and has no apparent eyes or mouth.

GREPTRIX          CR 4
XP 1,200
N Small aberration
Init +7; Senses blindsight 60 ft., darkvision 60 ft.; Perception +9


AC 19, touch 14, flat-footed 16 (+3 Dex, +5 natural, +1 size)
hp 47 (5d8+25)
Fort +5, Ref +4, Will +5
Defensive Abilities defensive curl; Resist acid 5, fire 5
Weaknesses vulnerable to cold


Speed 20 ft.; climb 20 ft.
Melee 4 tentacles +7 (1d3+3 plus grab)
Special Attacks control host, grasping tentacles, meld


Str 16, Dex 17, Con 18, Int 6, Wis 13, Cha 17
Base Atk +3; CMB +5 (+9 grapple); CMD 18
Feats Combat Reflexes, Improved Initiative, Toughness
Skills Perception +9, Stealth +15
SQ adrenaline rush
Language Aklo (can’t speak)


Environment any
Organization solitary
Treasure incidental


Adrenaline Rush (Ex) While melded to a host, a greptrix can deliver a surge of adrenaline to the host up to three times per day, granting a +4 enhancement bonus to Strength and Dexterity for one minute.

Control Host (Su) While melded to a host, a greptrix can attempt to gain control of the host’s body as a full-round action. The host must succeed on a Will save (DC = 10 + 1/2 the greptrix’s Hit Dice + the greptrix’s Charisma modifier + 1 per three days the greptrix has been melded to the host), or the greptrix gains control of the host’s body for 1d4 hours, as though with the spell possessionOA, during which time the greptrix remains melded to the host’s body. The greptrix can use this ability at will, but must wait 2d4 hours after each successful saving throw made by the host before using the ability again.

Defensive Curl (Ex) As a standard action, a greptrix can curl up into a ball, leaving only the armor-plated portions visible. This increases the greptrix’s natural armor bonus to +10, but renders it blind and unable to make attacks. A greptrix can uncurl itself as a swift action.

Grasping Tentacles (Ex) A greptrix gains a +2 bonus on grapple checks made to initiate a grapple for each tentacle attack it successfully hit that creature with this turn (to a maximum bonus of +8). Once the greptrix is successfully grappling a creature, it gains a +8 bonus to CMB for attempts to maintain the grapple, and a +8 bonus to CMD against attempts by the creature to escape or gain control of the grapple.

Meld (Ex) A greptrix that begins its turn with a Small or Medium creature pinned can attempt to meld with that creature as a suit of living armor. This requires a successful combat maneuver check. The target gains a bonus to their CMD for this check equal to 1/2 their armor bonus to AC, as heavy armor makes it difficult for the greptrix’s tendrils to attach to the host’s flesh. This counts as maintaining the grapple for the round, but if the check fails by less than 5, the greptrix maintains the grapple, even though it fails to meld with the host. If it fails by 5 or more, the grapple ends.

If the greptrix successfully melds with a creature, it makes its way under the creature’s clothing and armor and melds with its flesh, immediately causing any armor the creature was wearing to gain the broken condition and fall off. The greptrix then functions as a suit of armor that grants a +8 armor bonus to AC, with no maximum Dexterity bonus, no armor check penalty, and 15% arcane spell failure chance. Further, as long as the greptrix is melded, the first 5 points of bludgeoning, piercing, or slashing damage the host would suffer from any given attack is dealt to the greptrix instead.

While melded with a host, the greptrix sustains itself by draining a portion of the host’s life force. Each day, the host must make a Fortitude save (DC = 10 + 1/2 the host’s Hit Dice + the greptrix’s Constitution modifier), as the greptrix attempts to drain some of the creature’s life force for itself. On a success, the host’s Constitution score is reduced by 1d4 for 24 hours, but on a failure, it is reduced by 2d4, instead. This is not ability score damage, and cannot be healed with lesser restoration or similar effects. For each point of Constitution drained in this way, the greptrix gains a number of temporary hit points equal to its host’s Hit Dice, which last for 24 hours. Additionally, on any day that the greptrix has fed in this fashion (regardless of whether the host succeeds on its saving throw or not), the greptrix’s chitin plating hardens, and for the next 24 hours, the armor bonus to AC it provides to the host increases by 1 for every 4 Hit Dice the host possesses.

A greptrix that has melded with a host cannot be pried loose, and is physically grafted to the creature. A remove disease spell cast on the host forces the greptrix to succeed on a Fortitude save (at remove disease’s saving throw DC) or immediately unmeld, moving into an adjacent square. The greptrix can also be attacked directly: while melded, it loses its Dexterity bonus to AC, but it retains its size bonus and natural armor bonus. If its host is attempting to prevent the greptrix from being attacked, the greptrix adds the host’s Dexterity modifier to its AC. When the greptrix is attacked directly in this fashion, the first 5 points of bludgeoning, piercing, or slashing damage dealt to it by each attack is suffered by the host, instead. If the greptrix is slain, it immediately unmelds from the host.



These strange, parasitic creatures have adapted themselves to serving as exoskeletons for their host, living off the host’s life force and providing powerful defensive abilities in return. Their exact origin, and how they came to be such specialized symbiotes, is unknown. While some are willing to make the trade off of being fed on in order to reap the benefits the creatures provide, dark rumors persist that those who surrender themselves to the creatures wind up being controlled by them, rather than the other way around.