http://creaturecatalog.enworld.org/converted/pdf/aberration/xaver.pdf
Xaver
FREQUENCY: Very rare
NO. APPEARING: 1-4
ARMOR CLASS: 2
MOVE: 9”
HIT DICE: 2 + 4
% IN LAIR: See below
TREASURE TYPE: See below
NO. OF ATTACKS: 1 slash
DAMAGE/ATTACK: 2-5
SPECIAL ATTACKS: Metal corrosion
SPECIAL DEFENSES: Immune to metals, poisons, heat, and electricity
MAGIC RESISTANCE: 45%
INTELLIGENCE: Average to high
ALIGNMENT: Neutral
SIZE: S to M (3’ to 6’ tall)
PSIONIC ABILITY: Nil
Attack/Defense Modes: Nil
LEVEL/X.P. VALUE: IV/175 + 3/hp
Xavers are curious creatures of unknown origin and thankful rarity which, like rust monsters, have a diet consisting entirely of ferrous metals and alloys (such as iron, steel, and mithral or adamantite alloys). Unlike rust monsters, xavers are intelligent and will not be “bought off” with a meal of a few spikes or nails when they see an easily won suit of armor or much weaponry.
Xavers normally inhabit rocky lairs, but are sometimes found in treasure hoards in which they have concealed themselves. (Such hoards will have no ferrous materials in them, of course.) There is a 1% chance that any hoard initially determined to contain magical ferrous armor, shields, or weapons will also contain one or more xavers; then eliminate the metallic items from the hoard.
Xavers have silvery, smooth metallic bodies, and are flat and tapered with a bulbous base at one end. They resemble short swords or long swords. The ring of the base of a xaver is studded with six green, hard, faceted eyes that resemble gems. An 8-inch-long leg is set between each eye. A xaver lies motionless at the approach of creatures and radiates no body heat (thus being invisible to infravision) or sound. Instead of breathing, it absorbs solar heat and needed gases through the long “blade” of its body. It has no senses of hearing or smell, but has 9” infravision as well as normal vision.
Metal of any sort will pass harmlessly through a xaver’s body as if the latter did not exist, and metallic weapons used against the xaver will do no damage. Weapons of wood, stone, and other materials do normal damage. Heat and electrical attacks do no damage, but the xaver will conduct these through its body and pass the damage on to anyone in contact with it. A xaver suffers +1 hp per HD of damage from all cold attacks. Poison has no effect upon them.
Any ferrous metal that contacts a xaver will crack and fall into shards within 1 segment. The xaver will have caused the metal to corrode (though the corrosion does not resemble rust) and will then attempt to eat the metallic hards for nourishment. As a xaver eats metal it grows slightly; several suits of armor or about ten weapons might make one grow 1” or so.
Though xavers cannot control their corrosive powers, they can choose not to touch metallic items in order to lure victims wearing lots of armor to come closer to them. Non-ferrous metals will not be corroded and destroyed, though they can be consumed for nourishment if necessary.
Xavers scuttle about on their legs, retracting them with blinding speed if they see danger approaching. They can cut victims with the razor-sharp edges of their “blades” like wielded swords, doing 2-5 hp damage. Usually they swing their bodies in wild, circular slashes as they go into their “battle dancing”. Xavers do not rust or corrode, and rust monsters cannot harm or eat them.
A xaver about to give birth goes on an eating spree, building its body size to the maximum in order to provide sufficient nourishment for its offspring. Young are born live and singly, and have full powers at birth; young have 1 + 2 HD and are about 3” long, growing rapidly if the food supply allows.
Originally appeared in Dragon Magazine #94 (1985)
This is the Monstrous Compendium Annual Volume One version…
Xaver
Climate/Terrain: Any land
Frequency: Very rare
Organization: Solitary or family bands
Activity Cycle: Any
Diet: Ferrous metals
Intelligence: Average to high (8-14)
Treasure: See below
Alignment: Lawful neutral
No. Appearing: 1d4
Armor Class: 2
Movement: 9, Jp 3
Hit Dice: 3
THAC0: 17
No. of Attacks: 1
Damage/Attack: 1d4+1
Special Attacks: Metal corrosion
Special Defenses: See below
Magic Resistance: 45%
Size: S to M (3-6’ tall)
Morale: Elite (13-14)
XP Value: 270
A xaver looks exactly like a sword, with a hard, silvery body and six faceted green eyes that resemble gems around the hilt of a blade. Xavers are intelligent creatures that scuttle about on tiny, retractible, wormlike legs.
Like rust monsters, xavers eat ferrous metals (and alloys that include them such as steel and adamantine), but they are intelligent enough not to be bought off with a few spikes when they see an easily won suit of armor or much weaponry.
The body of a xaver is smooth and metallic, with a bulbous base at one end, tapering to a point at the other; the length between has flat side and sharp edges. An 8-inch-long, tentaclelike leg is set between each gemlike eye (the eyes ring the base of the body), but these legs are retracted at lightning speed if danger approaches. Xavers can see as humans do, and have 90-foot-range infravision. They do not hear or smell, and they give off no body heat or sound. They absorb solar heat and needed gases through their bodies, and lie motionless when creatures approach. Their bodies do not corrode until after death, and rust monsters cannot harm them.
Combat: Xavers cut opponents with the razor-sharp edges of their bladelike bodies. Usually they do a battle dance, swinging their bodies in wild circular slashes. Metal passes through a xaver’s body as if the latter did not exist. Heat and electrical attacks also inflict no damage, but the xaver’s body conducts these with full effects to all beings and items in contact with it. Poisons and venoms also have no effect on xavers, but cold-based attacks cause an extra point per die of damage.
Any ferrous metal touching a xaver cracks and falls into shards 1 segment later. The xaver will then try to eat the shards. Whenever a xaver can gorge itself, it grows slightly. A meal of several suits of armor or a dozen weapons or more might make one grow an inch in length. They cannot turn off their corrosive powers, but they can choose not to touch metallic items.
Habitat/Society: Xavers can go for many years without eating and are known to live for centuries. They are solitary, but wandering young, mating pairs, and a few that exhaust their food supplies can be found in small family groups. They never fight others of their own kind.
Xavers normally inhabit rocky lairs, but are sometimes found among treasure hoards in which they have concealed themselves. If a hoard is initially detemined to contain armor, shield, or weapons, there is a 4% chance that a xaver hasn’t yet managed to eat all the metal.
Xavers are bisexual. After mating, both partners go their separate ways and engage in eating sprees in order to provide sufficient nourishment for offspring. After 2d20 days, each parent gives birth to a single young xaver. Baby xavers have 1+2 HD, are about 3 feet long, and possess the full powers of an adult. If enough food is available, they’ll grow to full size within two months.
Ecology: Xavers eat ferrous metals and rust. Other types of metal don’t harm a xaver if ingested, but don’t give nourishment and are ejected later. Most coins consist of a base metal – sometimes ferrous – coated with a plating, so xavers often excrete masses of pure plating.
Fire lizards, xorn, remorhaz, and harpies (who must snatch xavers aloft and drop them from a height onto rocks to shatter their bodies) like xaver flesh, and a few other creatures will eat xavers if hungry enough.
Alchemists and wizards use powdered xaver bodies in spell inks, unguents, and alternative spellcasting components in spells involving resistance to heat and electrical energies, the rusting of metals, and in invulnerability to metallic weapons. Sold in the right place, a reasonably intact and fresh adult xaver body can bring as much as 1,600 gold pieces.