This person does a conversion of the Sand King from DOTA 2 to 3.5e.. There is lots of other homebrew material there too. This creature is suitable for Dark Sun.
Sand King Medium Magical Beast
Hit Dice : 4d10+16 (38)
Speed: 40 ft., burrow 20 ft.
Armor Class: 18 (+1 Dex, +7 natural)
Base Attack/Grapple: +4 / +7
Attack: Spear Arm +8 melee (1d6+3 plus poison)
Full Attack: 2 Spear Arms +8 melee (1d6+3 plus poison)
Space/Reach: 5 ft / 5 ft
Special Attacks: Burrowstrike, Poison
Special Qualities: Low-light Vision, Tremorsense 30 ft.
Saves: Fort +8, Ref +5, Will +1
Abilities: Str 16, Dex 12, Con 18, Int 2, Wis 10, Cha 6
Skills: Move Silently +8
Feats: Weapon Focus (Spear Arm), Ability Focus (Poison)
Environment: Warm deserts
Organization: Solitary, Pair, or Hive (3-8)
Challenge Rating: 3
Alignment: Always neutral
Advancement: 5-7 HD (Medium), 8-11 HD (Large), 12-16 HD (Huge)
Level Adjustment: –
This scorpion-like creature’s flattened body raises up at the front, almost forming a torso. In place of a stinger, it has a broad, spined tail and in place of pincers it’s arms sharpened to wicked points.
Burrowstrike (Ex): A sand king that burrows to the surface in a square containing a creature bursts forth in a spray of rock and sand while striking the target with its body. The target takes 2d6 of bludgeoning damage and must make a Reflex save (DC 15) or be knocked prone and blinded for 1 round. A successful save negates the prone and blindness and halves the damage. The save DC is Strength based.
A successful Listen check (opposed by the sand king’s Move Silently check) grants the defender a +2 bonus on this save.
On a failed save, the target is moved to an adjacent square and the sand king is now in the target’s square. On a successful save, the sand king emerges in an adjacent square.
Poison: A sand king’s poison deals 1d3 of dexterity damage as primary and secondary damage. The save DC for this sand king is 18.
Advancing a Sand King
Sand kings advance by Hit Dice. The damage from Burrowstrike should be a number of d6 equal to half the sand king’s HD.
A sand king that reaches 8 HD becomes Large and can affect multiple creatures with its Burrowstrike.
A sand king that reaches 12 HD becomes Huge.