VANADIS
FREQUENCY: Rare
NO. APPEARING: 1-12
ARMOR CLASS: 6
MOVE: //12-15.
HIT DICE: 2-8
% IN LAIR: 0%
TREASURE TYPE: Nil
NO. OF ATTACKS: 1
DAMAGE/ATTACK: Special
SPECIAL ATTACKS: Swallowing whole, continuous damage
SPECIAL DEFENSES: Bristles
MAGIC RESISTANCE: Standard
INTELLIGENCE: Non-
ALIGNMENT: Neutral
SIZE: L (1½-3. diameter; 10-20' long)
PSIONIC ABILITY: Nil
The Vanadis is a bristle worm that does not build a burrow. It is a good swimmer (it is AC 8 if motionless) and has large eyes with lenses in them, which afford this worm excellent vision.
The Vanadis feeds by everting its proboscis and swallowing its prey whole. It is not equipped with jaws, and thus the success of an attack depends only on the size of the prey (not the armor class). A Vanadis with 5 HD swallows a halfling on a roll of 14, an elf or dwarf on a roll of 15, a human on a roll of 17, and an ogre on a roll of 20. For each hit die which the worm has above five, subtract one from these values; add one for each die less than five. Creatures which require a roll above 20 are too large to swallow and will not be attacked. On the third round after swallowing, the prey is digested at a rate of 1-2 hp per round. Note that the prey is held tightly within the stomach, and is able to cut its way out from the inside only with great difficulty; only the use of a dagger is permitted.
A nice picture of it can be found
here.