Gem Crab

Gem Crab CR 1

A flicker of torchlight leads you a large pile of gold and gems, but one jewel in particular stands out to you and you feel a strong urge to pick it up and appraise its value.

XP 400
N Diminutive magical beast
Init +1; Senses tremorsense 60 ft.; Perception +7


AC 17, touch 16, flat-footed 15 (+2 Dex, +1 natural, +4 size)
hp 11 (2d10)
Fort +3, Ref +5, Will +0; DR 5/—


Speed 10 ft., climb 10 ft.
Melee bite +8 (1d6–3), claw +3 (2d4–3)
Space 1 ft.; Reach 0 ft.
Special Attacks compulsion gaze, dig in


Before Combat Gem crabs remain stationary and disguised, using compulsion gaze to urge creatures towards it so it can use dig in.

During Combat A gem crab bites and maims a victim until it has dealt 10 points of damage (removing a finger or toe as well as bestowing a temporary negative level that lasts for 1 minute).

Morale Gem crabs flee when reduced to 43 hp or less.


Str 5, Dex 14, Con 10, Int 5, Wis 10, Cha 18
Base Atk +2; CMB –5 (+10 when attached); CMD 7 (22 vs. grapple)
Feats Alertness, Weapon Finesse B
Skills Disguise +4 (+14 as gem), Perception +7, Sense Motive +2; Racial Modifiers +10 Disguise as gem
Languages varies


Dig In (Ex)

When a gem crab hits with its claw attack or is picked up as a result of its compulsion gaze, it grips onto the appendages of a creature like a vice and makes a free grapple combat maneuver check that does not provoke attacks of opportunity. Gem crabs have a +15 racial bonus on grapple checks and a +15 racial bonus to CMD when resisting a grapple. After a grapple is initiated, whenever a gem crab makes a successful combat maneuver check to grapple it deals its maximum bite damage and receives a free attack with its claw.

A grappling gem crab can be struck with a weapon (though creatures not grappled by it take a –4 penalty to attack rolls against it) or grappled itself; to remove an dug in gem crab through grappling, the opponent must successfully pin it.

Compulsion Gaze (Su)

Creatures within 30 ft. of a gem crab make a DC 15 Will save or are compelled to pick up and hold the creature; effectively, the creature unknowingly begins a grapple with the gem crab whenever they pick it up. The save DC is Charisma-based.

Varied Linguist (Su)

Once it has been with a host or owner for a week, a gem crab learns to speak that creature’s language. Its conversation is mostly about gems in general, their value, why creatures will want to take it from the owner, why the owner should do more to protect it, how the owner can gain more treasure, and why it deserves more of its own treasure.


Environment any
Organization solitary (in a chained-pendant), wristlet (3-5 embedded within), necklace (6-10 arrayed on a golden cord), treasure hoard (11-20)
Treasure standard

Gem crabs can appear to be any type of gem or jewel of any value, although like a hermit crab, gem crab moves from one jewel to another of ever increasing worth as it gets older and wishes to attract more victims. As a general rule, the shell of a gem crab is worth 20d10 gp x its HD. A gem crab never appears in the hoard of creature with more than twice its own HD.

A gem crab is an avaricious creature looking to gain a pile of its own treasure to rest on whenever possible, although it can never actually own or move anything. These curiosities sit on another creature’s possessions and instinctively prefer to be the most valuable item in a pile (often bringing it into conflict with the host owner). When its trespass is noticed the Diminutive magical beasts make deals to draw looters in and then help the host defend the pile, aiding in the defeat of would-be robbers (using compulsion gaze to distract enemies) If suitably flattered and given sufficient other gems to live on (at least twenty times the value of its own shell) a gem crab becomes a special familiar to a neutral or neutral evil wizard or sorcerer, granting its master a +3 bonus to Appraise checks. When it thinks its owner is not paying enough attention to it, a gem crab uses its compulsion gaze ability to be admired (though in this case it does not attack, soaking in vanity rather than blood).

Gem crabs range from barely an inch across to almost six inches in diameter; a gem crab is roughly one inch in diameter for every two Hit Dice. However, it is rumored that gem crabs of unimaginable size and power live and thrive on the Elemental Planes of Earth, a plane they have moved to and found to be to their liking. Tales of elder earth elementals battling with gem crabs the size of elephants can be found in the rarest of ancient Dwarven texts, although most consider them to be nothing more than children’s fables.

Section 15: Copyright Notice

Aventyr Bestiary © 2017 AAW GAMES LLC Authors Mike Myler, Jonathan G. Nelson Developers, Michael Allen, Curtis Baum, Wolfgang Baur, Brian Berg, Adam Daigle, Jeffrey Gomez, Joshua Gullion, Jacob Kellogg, Jared Jeanquart, Juan Lucha, Justin Andrew Mason, Jonathan McAnulty, Michael McCarthy, Raven Mimura, Brian Wiborg Monster, Will Myers, Mike Myler, Jason Nelson, Jonathan G. Nelson, Owen K.C. Stephens, Colin Stricklin, Cory Vickruck, Stephen Yeardley Jonathan G. Nelson

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