IRONBONES 

The dreaded ironbones are an undead, similar to a zombie in many ways, of preternatural toughness and rudimentary intelligence. They are created by ritual from exceptionally fresh or preserved corpses and a spirit of iron called and bound to the body which, in reaction, is forced to change to accomadate the entity. The body's bones become solid iron, its skin tough like hide, and its stomach a crucible. Slow and plodding, their footsteps heavy and dull, they are implacable foes for the spirit that animates the body, dull and unintelligent, gladly kills for the master that bound them. They need no sustenance but are known to devour iron and steel, eating nails and the arms and armour of their fallen enemies. In this they must be appeased and if not given enough metal to eat they have been known to find some on their own, sometimes to their master's eventual misfortune. 

"I was saved once, by these beings' tendency for siderophagy. I had been captured by a necromancer who had created himself an ironbones, and set it to guard me in my cell. The wizard, as it turned out, had failed to maintain a steady diet for the creature. After a few hours of what must have been sheer temptation it began to eat the bars of my cell. It was, I will admit, not the most glamourous of escapes, but any escape is a good escape." -EC 

Ironbones (Undead Type 8): #E 1 (1d2)|AL CE|SZ M|MV 20|DX 5|AC 0|HD 5+10|#A 2/1 (pummel)|D 2d6 (x2)|SV 14|ML 12|XP 620|TC Nil| Special:
Grab: If an ironbones hits with both pummel attacks it may grab the victim, requiring an extraordinary feat of strength or dexterity to escape (an ironbones has 18 strength). There is a 1-in-4 chance the ironbones will make a bite attack at +2 to hit and dealing 2d8 hp damage, otherwise the monster will generally toss the victim about, throwing them into walls or on the floor or into the poor victim's companions, dealing 1d6+3 hp damage and requiring an extraordinary feat of dexterity or be knocked prone.
Bones of Iron: With its entire skeletal structure replaced with solid iron, an ironbones is heavy, around 400 lbs. It is difficult to push around an ironbones, and they receive +4 to their saving throws to resist being shoved. They cannot float in water, instead sinking straight to the bottom. Rust monsters have a tendency to be attracted to these creatures, though they tend to be frustrated by their inability to reach the metal beneath the dead flesh. For their part, ironbones will attack and kill rust monsters; after all they compete for the same... food source. If one were to de-flesh a fallen ironbones, the recovered magically infused metal could be melted down and used in the creation of arms and armour. The resultant item is a magic +1 item, though there is a 2-in-6 chance that the item comes out cursed.
Immunities: Immune to cold, fear, paralysis, and poison.
Resistances: Ironbones take 1/2 damage from slashing, piercing, and bludgeoning attacks.
Vulnerability: There is a special powder that can be made which makes an ironbones vulnerable. To make the powder requires a witch or an alchemist, 5d4x10 gp, and 1d4 days. When thrown on an ironbones as a grenade attack, the creature has AC 8 and must make a spell save or be stunned for 2d4 rounds. The AC penalty remains until the dust is cleaned off.
Slow: Always attacks last on initiative; no running movement allowed.