Olgoi-Khorkhoi (Mongolian Death Worm)Hit Dice: 4-6
Armor Class: 7 
Attacks: Spew poison
Saving Throw: 13, 12 or 11
Special: Poison, lightning, corrosion
Challenge Level/XP: 4 HD: 9/1,100; 5 HD: 10/1,400; 6 HD: 11/1,700
An Olgoi-Khorkhoi is a bright red worm varying from 2' to 4' in length. It has no head, only a gaping maw that drips venom. Most of the life of these creatures is spent burrowed in sandy or rocky soil, only coming out to hunt a few times a year. Its preferred target are camels and pack animals in general, which they use to lay their eggs, but they will attack humans.
A 2' worm will have 4 HD, 3' having 5 HD and 4' with 6 HD. The death worm has an electric shock that it can use once per day; this is a lightning bolt for a number of d6 equal to its hit dice. If encountered at a distance the olgoi-khorkhoi will always use its shock as a first weapon. Subsequently, it can spit venom up to 5'. On a successful hit, a target must save versus poison or die. If this is unsuccessful, there is a 1 in 6 chance that a character in metal armor is hit by the spray. This will corrode the armor beyond use.
The body of the olgoi-khorkoi is entirely venomous and corrosive. If a metal weapon is used against the death worm, there is a 3 in 6 chance of it being affected and corroded beyond use after the combat (subtract any bonus on a magic weapon from this chance). Any character touching the skin of the death worm must make a saving throw versus poison at +2 or die. Both dangers continue to exist after the creature itself dies.
A dead olgoi-khorkhoi's body is a valuable resource, that may be purchased by wizards, alchemists or assassins. As a rule of thumb, each foot of body weighs 25 lbs. and fetches 500-1000 GP, up to a maximum of 4000 for a 6 HD monster.