Cistern Creeper

Medium aberration, neutral evil

Armor Class: 15 (Natural Armor)
Hit Points: 60 (8d8 + 24)
Speed: 20 ft., swim 40 ft.

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Ability Scores:

STR	DEX	CON	INT	WIS	CHA
12 (+1)	16 (+3)	16 (+3)	4 (–3)	14 (+2)	6 (–2)

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Saving Throws: Dex +5, Con +5, Wis +4
Skills: Stealth +7, Perception +4
Senses: Darkvision 60 ft., passive Perception 14
Languages: Understands Deep Speech but cannot speak
Challenge: 4 (1,100 XP)

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Traits:

• Amphibious: The Cistern Creeper can breathe both air and water.
• Regeneration: While in water, the Cistern Creeper regains 5 hit points at the start of its turn. If it takes acid or sonic damage, this regeneration ceases until the start of its next turn.
• Stealthy Ambusher: In dim light or darkness, the Cistern Creeper can use the Hide action as a bonus action.

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Actions:

• Multiattack: The Cistern Creeper makes one Tentacle attack and one Claw attack.
• Tentacle:
  • Melee Weapon Attack: +5 to hit, reach 10 ft., one target.
  • Hit: 10 (2d6 + 3) bludgeoning damage plus 3 (1d6) piercing damage.
  • Grapple: On a hit, the target is grappled (escape DC 13) and is restrained until the grapple ends.
• Claw:
  • Melee Weapon Attack: +5 to hit, reach 5 ft., one target.
  • Hit: 8 (1d8 + 3) slashing damage.
• Tangling Tentacles (Recharge 5–6):
  • The Cistern Creeper unleashes its remaining tentacles in a 15-foot cone.
  • Each creature in that area must succeed on a DC 13 Dexterity saving throw or be restrained until the end of its next turn.
  • On a successful save, a creature’s speed is halved until the end of its next turn.
• Water’s Embrace (Recharge 6):
  • The Cistern Creeper summons a swirling mist of water in a 10-foot radius centered on itself.
  • The area becomes heavily obscured until the start of its next turn, and any ranged attack targeting the creature is made at disadvantage.

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Reactions:

• Grasping Reflex: When a creature within 5 feet of the Cistern Creeper makes a melee attack against a target other than the Creeper, it can use its reaction to make a Tentacle attack against that creature.

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Tactics:

• Ambush Predator: Lurking in the shadows of dank cisterns and watery recesses, the Cistern Creeper uses its natural stealth to ambush isolated foes. If it surprises its prey, its first attack gains advantage.
• Grapple and Strike: It focuses on grappling a single target with its Tentacle, restraining the victim to then follow up with vicious Claw attacks.
• Regenerative Retreat: When reduced to half its hit points and if water is nearby, the Creeper will retreat into a watery refuge to benefit from its regeneration trait while harrying foes from the darkness.

This squat creature has a rubbery body shaped roughly like a mushroom. Bulbous eyes glare from over a short proboscis. Eight tentacles grow from its body, each tipped with a pincer.

Taken from the Creature Codex

Cistern creepers are strange subterranean horrors that lurk in aquifers, wells and other groundwater sources. Their flexible bodies allow them to squeeze through even tiny cracks, and cistern creepers can turn up in unexpected places with ease. They are rarely seen aboveground except on dark and rainy nights.

A cistern creeper can survive indefinitely by absorbing minerals dissolved in water, but they must kill larger creatures in order to reproduce. Cistern creepers are sexless, and a cistern creeper reproduces by injecting some of itself into the corpse of a Medium-sized or larger creature. Over the course of a week, the tissue of the body transforms into a rough tentacled mass and pulls itself free, whereupon it disperses to a body of water of its own. Cistern creepers can reproduce repeatedly as long as they have access to victims, allowing populations of these monsters to reach plague proportions quickly if they are not stopped.

A cistern creeper is about three feet tall and almost spherical in shape, with tentacles that reach another three feet. They are light for their size, weighing approximately fifty pounds.

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Cistern Creeper CR 9

XP 6,400
NE Small aberration (aquatic)
Init +10; Senses darkvision 120 ft., Perception +12

Defense

AC 22, touch 17, flat-footed 16(+1 size, +6 Dex, +5 natural)
hp 119 (14d8+56), regeneration 3 (acid or sonic)
Fort +8, Ref +10, Will +12
Resist cold 10, electricity 10

Offense

Speed 20 ft., swim 40 ft.
Melee 8 claws +17 (1d4+1)
Special Attacks rend (4 claws, 1d4+1), tangling tentacles

Statistics

Str 13, Dex 22, Con 18, Int 6, Wis17, Cha 9
Base Atk +10; CMB +10; CMD 30 (cannot be tripped)
Feats Blind-fight,Combat Reflexes, Defensive Combat Training,Improved Initiative, Power Attack, Skill Focus (Stealth), Weapon Finesse
Skills Climb +15, Perception +12, Stealth +22, Swim +23; Racial Modifiers uses Dexterity for Climb and Swim
Languages Aklo (cannot speak)
SQ amphibious, compression

• Ecology

Environment underground and aquatic
Organization solitary or pair
Treasure incidental

Special Abilities

Regeneration (Ex) A cistern creeper’s regeneration only functions if the cistern creeper is touching water.

Tangling Tentacles (Ex) Any creature that ends its turn adjacent to a cistern creeper must succeed on a DC 23 Reflex save or become entangled in the creature’s tentacles. An entangled creature cannot leave the square it is in and remains entangled until it succeeds a combat maneuver or Escape Artist check against the cistern creeper’s CMD. This condition ends if the cistern creeper moves away from the entangled creature. The save DC is Dexterity based.