"S" is for "Sandseal"

Sandseal

No. Enc.:  0 (1d8)
Alignment:  Neutral
Movement:  150' (50')
Armor Class:  3
Hit Dice:  5
Attacks:  2 claws, 1 (bite)
Damage:  1d4 / 1d4 / 1d6
Save:  L3
Morale:  9
Hoard Class:  None
XP:  650

Top predators of the desert wastes, the powerful, 10'-12' sandseals glide effortlessly beneath the barren landscape.  

Sandseals hunt in packs, and burst forth from the ground (Surprising on a 1-4 on 1d6) to grab unsuspecting prey, and then drag it beneath the shifting grit.  In addition to taking automatic biting damage each round, anyone pulled under for more than 3 rounds must make a Saving Throw Versus Death, or suffocate.  (Those with proper environmental gear get a +3 bonus to the roll, but must still Save due to clogging and contamination.)  The suffocation Save must be made each round until free of the beast's jaws.

At night, the forlorn barks of the sandseals echo across the badlands.

Mutations:  Echolocation