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Pebble-Hide Swimmer - AI-generated fantasy Monster

Pebble-Hide Swimmer

The Windward Plains are known for their deceptive beauty. Local guides tell of 'Walking Rivers' where the very floor of the water rises up to swallow those who don't watch their step. These elementals are thought to be fragments of the earth that were smoothed by centuries of celestial winds and water, eventually gaining a predatory spark.

Monsters
Medium elemental · CR 3 · Rare

Pebble-Hide Swimmer

Living riverbeds that act as geological ambush predators in serene plains.
AC17
HP52/52
CR3
Init
STR
DEX
CON
INT
WIS
CHA
ConditionsNone

Combat

AC 17 · HP 52 · CR 3

Pebble-Hide Swimmer

Medium elemental (beast), neutral
Armor Class17 (Natural Armor)
Hit Points52 (7d8 + 28)
Speed
20 ft. walk,
40 ft. swim
STR
DEX
CON
INT
WIS
CHA
Saving ThrowsStrengthConstitution
SkillsStealthPerceptionAthletics
Damage Resistances
Piercing and slashing from nonmagical attacks
Immunities
Poison
Weaknesses
None
Senses
Darkvision 60 ft.,
Tremorsense 30 ft. (while in contact with water or stone),
Passive Perception 13
Languages
None
Challenge3
Proficiency Bonus+2
False Appearance. While the swimmer remains motionless, it is indistinguishable from a mundane rocky riverbed.
Hold Breath. The swimmer can hold its breath for 1 hour.
Weight of Stone. The swimmer has advantage on Strength (Athletics) checks made to grapple a creature and on saving throws against being moved.

Actions

Multiattack. The swimmer makes two attacks: one with its bite and one with its tail.
Bite. Melee Weapon Attack: to hit, reach 5 ft., one target. Hit: 12 () piercing damage. If the target is Medium or smaller, it is grappled (escape ). Until this grapple ends, the target is restrained, and the swimmer cannot bite another target.
Tail Slap. Melee Weapon Attack: to hit, reach 5 ft., one target. Hit: 7 () bludgeoning damage. If the target is a creature, it must succeed on a Strength saving throw or be knocked prone.
Drown in Silt. The swimmer makes a Bite attack against a grappled creature. If the attack hits, the target takes an extra 7 () bludgeoning damage and is pulled 5 feet under the silt/water surface if applicable. The target begins suffocating if it cannot breathe underwater.

Reactions

Stone Snap. When a creature moves into the swimmer's space or steps on it while it is camouflaged, the swimmer can make one bite attack with advantage against that creature.
Role
Ambush Tank
Built for
4

Gear

  • The Aviary Compass (Wondrous Item, 500 gp)A brass compass with a spinning feather instead of a needle. It grants the wielder advantage on Wisdom (Survival) checks to find high ground or avoid natural hazards while in plains or mountains.

Feats

Grappler

Notes for the game master

Focus on keeping targets prone and submerged.
Use the natural AC to shrug off standard arrow fire from the banks.

Tactics

  1. Opening

    Wait for at least two party members to be in the middle of the river, then use Stone Snap on the character with the lowest Strength.

  2. Mid-fight

    Alternate between Bite and Tail Slap. Use the movement speed in water to drag grappled targets away from their allies.

  3. End of the fight

    If multiple swimmers are present, they attempt to form a wall to prevent the party from reaching the Aviary Compass.

  4. Retreat

    If reduced to below 10 HP, the swimmer will sink into the deepest silt and remain motionless, hoping its False Appearance will save it.

How it fights

Attack from beneath. Use the river's depth to gain partial cover (+2 AC) while attacking.
Focus on restraining the party's movement to prevent them from reaching the riverbank.

Who it attacks first

The creature stepping directly on the swimmer's back.
Spellcasters standing in the shallows.
Anyone attempting to pick up the Aviary Compass.

Works well with

Works well with Water Weirds or Mud Mephits which can distract or blind targets while the Swimmers grapple.
Pairs with environment hazards like Slippery Rocks or Strong Currents.

How to beat it

Thunder damage (causes the stones to crack/vibrate, granting disadvantage on its next attack).
Spells like Control Water or Destroy Water to reveal their positions.

Ways to avoid a fight

Offer the creature high-quality raw ore or gems; it may allow passage or move aside if fed.
Perform a DC 15 Nature check to identify the patterns in the 'rocks' before stepping on them.

Ecology

At a glance, these creatures resemble a three-foot long section of riverbed composed of perfectly smooth, variegated river stones. Closer inspection reveals the 'stones' are actually thick, interlocking osteoderms. They have the low, powerful silhouette of a crocodilian with pale opal eyes and a mouth filled with jagged flint-like teeth.

Behavior

Extremely patient. They can remain motionless for days, allowing algae and silt to accumulate on their backs to perfect their camouflage. They only move when prey puts weight directly on their spines or attempts to dredge the silt where they hide.

How it lives

Pebble-Hide Swimmers do not hunt actively. They are lithovores that supplement their mineral intake by crushing organic prey and absorbing the nutrients released into the water during the struggle.

Lair

They do not maintain traditional lairs, instead colonizing specific shallow 'killing reaches' of a river where the current slows down naturally.

Habitat
Shallow rivers, mountain runoff streams, and valley floodplains.

Signs that it is near

Unusually clear water in one specific area
Missing wildlife tracks leading into the water but not out
A rhythmic grinding sound like millstones coming from underwater
Perfectly rectangular arrangements of smooth stones

Tags

amphibious,
earth-elemental,
ambusher

Lore

The Windward Plains are known for their deceptive beauty. Local guides tell of 'Walking Rivers' where the very floor of the water rises up to swallow those who don't watch their step. These elementals are thought to be fragments of the earth that were smoothed by centuries of celestial winds and water, eventually gaining a predatory spark.

What drives it

Territorial defense and passive feeding. They are currently clustered around a sunken cache containing the Aviary Compass, drawn to its faint hum.

After the fight

Once defeated, the creature turns back into a pile of mundane river stones over the course of an hour. The water in the area becomes murky with grit and silt for several days.

“Local guides tell of 'Walking Rivers' where the very floor of the water rises up to swallow those who don't watch their step.”
From its lore

Variants

Moss-Back Swimmer: Has a higher Stealth bonus (+10) and can use a reaction to release a cloud of obscuring spores.
Obsidian-Edge Swimmer: Deals additional fire damage with its bite and has resistance to fire.

Hooks

Plot hooks

A local caravan lost a valuable shipment of sky-glass in the shallow rapids, but the searchers never returned.
The Aviary Compass is needed to find the hidden path to the Cloud Giant's reach, but the river it fell into has 'come alive'.

How to use it

A river crossing 'hazard' where the hazard is actually alive.
Guardians of a sunken ruin in the Windward Plains.

Treasure

The Aviary Compass (found in the silt).
Assorted gems (worth 100 gp) stuck in the creature's hide.

Media

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