Available at floating island caves in Crystal Isles.
They're very rare in there so be patient

They spawn in Genesis in several caves in the Lunar biome

It's a Giant crab that can throw it's enemies far away

Make sure to carry around grappling hooks
If picked you can graple the crab and it will let go

Will rip you off tame I repeat TAKE YOU PFF YOUR TAME AND KILL YOU EASY

This is a angry crab that you should not get near or it will rip your toes off and use your lungs as a doormat

On crystal isles,these are an easy find in the river that surrounds the biggest yellow crystal at the Eastern floating islands.

Easily at least 8 there at a time. Be sure to look at all the small lakes in the area you can find 2 in each of them at anytime.

Kill and use chainsaw for organic polymer or even better use a moschops spec’d into organic farm to really increase that organic poly farm easily

Giant crab jumps super high, almost has a heart attack, the spawn in Lunar caves!

In the wild crabs and spinos are buddies... they use the buddy system...

They can walk over spiked walls.

I killed one with just a bow and movement speed back up shoot turn around and run a little turn and shoot easy way to kill plus lots of chitin and organic polymer easy just bring enough ammo

Unless I am missing something, the Quetzal CANNOT pick up the Karkinos with their feet.

It'll drop you if you log out.

Has a slow reaction time and you can usually avoid it attacking you by running under its legs.This might change in later patches

They often spawn near the lake by the portal in aberration so if your looking for one be careful and don’t swim to deep!

They drop Organic Polymer when you harvest their corpse

can be found along with ravagers and other creatures on Valguero. northeast of map, look for underground waterfall.

Can be used to tame aggres-passive dinos (e.g arthropluera) more easily by grabbing them since it doesn't drop them when you dismount like argentavis.

Throwing a plant z grenade can cause a Karkinos to drop you or your dino. Essential when traveling on Ravenger back.