Rock Lobster

Imagine an angry rock with claws that that can snap bone and shear metal that uses its tail to hurl itself at your fleshy bits about as fast as a village child can sling a pebble while hunting. That about sums up the rock lobster, terrifying things.

— Jasper Cameron, Leader of the Bronze Ravens

It was stupid, but what else could we do. We fled the rest of the Brigade. This desert is death and we never should have come here, orders be dammed. Lyrebirds lured us in to patch after patch of Harpoon Cactus. Some idiot managed to break into a hive of the bees. its not like cooking in flames. You dont get the smell of burning hair, just the screams of men and horses as they are rather efficiently roasted, and the smell of cooking meat. But the worst is the canyons. 
"This way, there aren't any of those bloody cactuses." That probably should have been our warning. Near a hundred of us had managed to group up and stay together, we even had 10 scouts with us. But if the cactus avoid a place near where so many others of their kind thrive we should have known. We started towards the hills, glad to see a way out. 
At first it looked like an ambush. The two lead riders were struck and toppled off of their horses. then the horses also collapsed, screaming as only horses can. next thing we knew the evening was filled with what we thought were rocks. Except rocks dont shear off hands and feet. Rocks may break a horses ankle, but they dont sever it clean.
Twelve of us made it out of that death trap. The slope ran thick with the blood of the men and horses that didnt make it. I think I know now where the moisture for the cactuses at the base of the slope comes from.
-Excert of a journal found in the Myrdhor Desert believed to have belonged to a member of The Charred Brigade.

Basic Information

Anatomy

While similar in appearance to the marine lobster, it should be noted that Rock lobsters are very likely a separate banch of evolution.
Thier most unique feature, at least as far as the animal kingdom is concerned, is their main form of locomotion. While They do have legs and are capable of walking, they rarely do so. Instead, they will flatten their tail out onto the ground and then snap it into the curl more often associated with lobster tails. This snap propels them through the air towards their intended victim, where their claws usually ensure the demise of their chosen target. 
Speaking of claws, similar to marine species the claws are specialized between right and left. The left claw is used for cutting, slicing, crushing, shearing and otherwise rendering the lobsters prey into nice bite sized pieces. Whether due to some magic of its environment or the filtering out of minerals in its diet these claws are more than capable of shearing through most metals, making plate (if one were stupid enough to wear it in the Desert) little protection.
Its is in the second claw, through, that we see the true horror and genius of Nature. Take a barbed broad-head arrow and rotate is around itself so you have a solid harpoon shape. Now cut it in half lengthwise and put a hinge in the base that allows the harpoon to be forced open making it even harder to remove and ensuring that even more blood is lost through the channels that nature cleverly put into the harpoons design.
Of course, in the Myrdhor the scent of blood just draws predator and scavenger alike, which is why the attack of even a single rock lobster often proves fatal to all but the most resourceful creatures.

Dietary Needs and Habits

As ambush predators in a desert, the Lobsters are evolved to go long periods of time without food or water, laying their antenna on the ground and entering a near hibernation state. According to druids this state can last for years, as the outer carapace of a rock lobster is exceedingly good at preventing moisture loss.
Once prey is caught, the lobsters will gorge themselves. The blood of the victim, in addition to providing the moisture needed to survive, also plays a key roll is the growth of lobsters. While the outer carapace is quite hard, once it is wetted it becomes much more soft and fragile. This allows the recently gorged lobster to split out of its old shell and grow a new larger one. Should the Prey be large enough this can happen several times before the lobster goes back into hibernation.
Oddly enough, despite being more than capable of processing bone down to eatable size, rock lobsters no not consume the bones of their victims. Once a majority of the blood has been drained, the lobsters move away from the corpse and allow their new shell to harden.

Additional Information

Perception and Sensory Capabilities

While they do have eyes, the most developed senses in rock lobsters are their sense of touch and smell. The first lobster in an area usually attacks its prey by sensing the vibrations it the creatures movement. Should its attack prove successful, the subsequent lobsters, if any, smell the blood and are able to launch even more accurate attacks.

Geographic Distribution

• Myrdhor Desert