Missing Monsters - K’cin Crawler

It was pointed out to me by Rovewin of Athas.org, that the k’cin crawler is mentioned in the Revised Dark Sun Boxed Set. However, they are not drawn up in that, or any other book. So, in an effort to rectify the situation, I have created the k’cin crawler below.

K’cin Crawler
Climate/Terrain: Rocky Badlands, Stony Barrens
Frequency: Uncommon
Organization: Solitary
Activity Cycle: Anytime
Diet: Omnivore
Intelligence: Animal (1)
Treasure: None
Alignment: Neutral
No. Appearing: 1-2
Armor Class: 4
Movement: 6
Hit Dice: 3
Thac0: 17
No. of Attacks: 3
Damage/Attacks: 1-2/ 1-2/ 1-4
Special Attack: None
Special Defense: Hide in shell
Magic Resistance: Nil
Size: L (8' tall)
Morale: Unreliable (2-4)
XP Value: 35

K’cin Crawler
The k'cin crawler is an eight foot tall and eight foot long, eight-limbed anthropod used as a beast of burden outside of the Tablelands.

Combat
K'cin crawlers would much rather run than fight, but if pressed into combat, will claw and bite for 1d2 damage per claw and 1d4 for a bite. If reduced to a quarter of their hit points, the k'cin crawler will pull into its shell, improving it's armor class by four, but reducing its number of attacks to only one claw attack per round.

Habitat/Society
K'cin crawlers are prized beasts of burden, as they only require a gallon of water every five days. They are slow, but are extremely easy to domesticate and can carry up to six-hundred pounds. They also live for up to a hundred years.
K'cin crawlers mate once every season and lay a clutch of 1-4 eggs, which hatch 3 months later. They have four major points in their life:
Newly hatched k'cin crawlers are small, have 1 hit dice, have an armor class of 5, and have one attack, one bite causing 1 point of damage. They can carry 100 pounds. This phase of their life lasts for eight years.
Young k'cin crawlers are medium-sized, have 2 hit dice, have an armor class of 4, and have three attacks, two claws doing 1 point of damage each and a bite doing 1-2 points of damage. They can carry 400 pounds. This phase of the their life lasts for twelve years.
They enter their adult phase, which is detailed above. This phase of their life lasts for sixty years.
After their adult phase, k'cin crawlers get old. Old k'cin crawlers grow to a very large size, becoming huge, and their armor class improves to 1. The damage of their attacks become 1-4, 1-4 per claw and 1-6 for its bite. Old k'cin also become confused easily and are temperamental. They are much more prone to disobey their owners and randomly attack anything that passes in front of them. Most k'cin crawlers are killed when they grow to old age.

Ecology
K'cin crawlers form an important part of the athasian food chain. They prefer to eat carrion and other easily accessable food sources. The shell of the k'cin crawler is rock-like and cannot be worked into any usable object. However, certain settlements use the large and huge shells of dead adult and old k'cin crawlers as shelters. K'cin do provide a buttery and nutty flavored meat equal to it's hit dice multiplied by ten. Each pound of k'cin crawler meat sells for 2 bits per pound.