Monster Monday: Mantis Shrimp - The Fastest Claws in the Sea

Today's Monster Monday is the giant mantis shrimp, a man-sized version of the little rainbow-colored tropical shrimp that can punch so fast they boil the water around their claws and create a shockwave, and whose eyes are so good they can see colors we can't even imagine.

photo by prilfish from Vienna, Austria, via Wikimedia

If you've been on the internet in the last few years, you may have noticed a growing interest in these fascinating, terrifying, badass little rainbow murder shrimp.  Now you can bring that interest to your gaming table!

photo by SSR2000, via Wikimedia

WHOA! THAT IS FREAKY!

The following text in gold is available as Open Game Content under the OGL. Open Game Content is ©2015 Jonah Bomgaars.

Giant Mantis Shrimp (Smasher)      CR 5

XP 1,600

N Medium vermin (aquatic)

Init +7; Senses low-light vision, darkvision 60 ft., extraordinary vision; Perception +20

DEFENSE

AC 19, touch 13, flat-footed 16 (+3 Dex, +6 natural)

hp 52 (8d8+16)

Fort +8, Ref +5, Will +7

Immune illusions

Weakness water dependency

OFFENSE

Speed 20 ft., swim 40 ft.

Melee hammer-claw +11 (1d8+4 plus cavitation) and spear-claw +10 (1d6+4 plus cavitation)

STATISTICS

Str 18, Dex 16, Con 14, Int 1, Wis 20, Cha 17

Base Atk +6; CMB +10 (+14 sunder); CMD 23 (35 vs trip)

Feats Improved Initiative, Lunge, Skill Focus (Perception), Weapon Focus (hammer-claw)

Skills Perception +20, Swim +16; Racial Modifiers +8 Perception, +8 Swim

SQ extraordinary vision, shell-cracker

SPECIAL ABILITIES

Cavitation (Ex)

The mantis shrimp’s claws strike so fast that their movement creates a shockwave of collapsing bubbles in the water.  When a mantis shrimp successfully hits a target in the water, roll the damage dice twice, adding any bonuses only once.  This functions like the Vital Strike feat, except it applies to all attacks the mantis shrimp makes underwater. 

   Any creature hit by the mantis shrimp’s cavitation must make a DC 16 Fortitude save or be stunned for one round.  All creatures in the same 5-foot square that the mantis shrimp attacks but which are not hit by either claw must still make a DC 11 Fortitude save or be stunned for one round.  The save DCs are Constitution-based (a -5 penalty is included in the secondary effect’s save).

Extraordinary Vision (Ex)

Mantis shrimp have some of the most complex eyes in the natural world.  Aside from allowing them to see colors unimaginable to most other beings, their eyes grant the mantis shrimp the ability to see invisible creatures and see through normal and magical darkness.  They are also immune to all illusions and can see through effects like blur or displacement.  In addition, this grants the mantis shrimp a +8 racial bonus to their perception checks. 

Shell-Cracker (Ex)

Smasher mantis shrimp use their claws to break the tough shells of their prey open.  They gain a +4 racial bonus on Sunder attempts. 

Water Dependency (Ex)

A giant mantis shrimp can survive out of water for 1 minute per 2 points of Constitution.  Beyond this limit, it runs the risk of suffocation, as if it were drowning. 

ECOLOGY

Environment warm ocean

Organization solitary

Treasure incidental

Giant Mantis Shrimp (Spearer)         CR 5

XP 1,600

N Medium vermin (aquatic)

Init +7; Senses low-light vision, darkvision 60 ft., extraordinary vision; Perception +20

DEFENSE

AC 19, touch 13, flat-footed 16 (+3 Dex, +6 natural)

hp 52 (8d8+16)

Fort +8, Ref +5, Will +7

Immune illusions

Weakness water dependency

OFFENSE

Speed 20 ft., swim 40 ft.

Melee 2 spear-claws +11 (1d8+4 plus 1 bleed plus grab)

Special Attacks barbed claws, rend (1d8+6)

STATISTICS

Str 18, Dex 16, Con 14, Int 1, Wis 20, Cha 17

Base Atk +6; CMB +10 (+14 grapple); CMD 23 (35 vs trip)

Feats Improved Initiative, Lunge, Skill Focus (Perception), Weapon Focus (spear-claw)

Skills Perception +20, Swim +16; Racial Modifiers +8 Perception, +8 Swim

SQ extraordinary vision

SPECIAL ABILITIES

Extraordinary Vision (Ex)

Mantis shrimp have some of the most complex eyes in the natural world.  Aside from allowing them to see colors unimaginable to most other beings, their eyes grant the mantis shrimp the ability to see invisible creatures and see through normal and magical darkness.  They are also immune to all illusions and can see through effects like blur or displacement.  In addition, this grants the mantis shrimp a +8 racial bonus to their perception checks. 

Barbed Claws (Ex)

Smasher mantis shrimp use their barbed spear-claws to hold and rend their soft prey.  They gain a +4 racial bonus to initiate and maintain a Grapple.  Their claws do piercing and slashing damage, and a creature struck by them takes 1 point of bleed damage.

Water Dependency (Ex)

A giant mantis shrimp can survive out of water for 1 minute per 2 points of Constitution.  Beyond this limit, it runs the risk of suffocation, as if it were drowning. 

ECOLOGY

Environment warm ocean

Organization solitary

Treasure incidental

Despite their vibrant coloration, giant mantis shrimp are the terrors of shallow tropical waters.  They lash out with their highly specialized claws at tremendous speeds to spear or stun their prey.  Smasher mantis shrimp have a blunt hammer-claw and a less-developed spear claw which they use in tandem to crack open tough shells.  They strike so fast that they create a shockwave in the water that can stun their prey.  Spearer mantis shrimp have two powerful spear-claws covered with slashing barbs that let them grip and rip their soft-bodied prey of choice.  Both species’ eyes are incredibly well-developed, allowing them to see even invisible opponents. 

   Giant mantis shrimp make burrows in sand, coral, or rock in shallow waters.  This often puts them at odds with fishermen, clam-divers, and unwary beach-goers who stumble into their territory and find the bright, man-sized crustaceans darting out to break their legs or spear them through the gut.  Some aquatic humanoids, like locathah and merfolk, train giant mantis shrimp as guard animals.  

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Here are some potential hooks to include giant mantis shrimp in your game (because I'm assuming most campaigns don't take place entirely in shallow tropical waters).

• Pearl divers are complaining that a fierce, deadly, brightly colored monster has moved into the best foraging grounds, and they refuse to go back in the water until it has been killed.
• A ship just returned from a long voyage to uncharted waters and thought to contain great treasure was shipwrecked by a storm not far from shore, but none who have gone to investigate have returned.  
• A tribe of locathah have fallen under the sway of a dark god and are kidnapping fishermen for sacrifice.  Their coral cave lair features several fully or partially submerged chambers filled with numerous guardian beasts, including the dreaded mantis shrimp.  
• Oh, you thought that was an interesting tide pool?  Wha-CHA!  MANTIS SHRIMP!

-your trinocular d20 despot