|This material is published under the OGL|
|Hit Dice:||6d10+32 (65 hp)|
|Speed:||20 ft., climb 20 ft.|
|Armor Class:||4 (-2 size, -4 Dex), touch 4, flat-footed 4|
|Attack:||Slam +4 melee (1d8 and 1d6 cold)|
|Full Attack:||Slam +4 melee (1d8 and 1d6 cold)|
|Space/Reach:||15 ft./10 ft.|
|Special Attacks:||Cold, Engulf, Skeletons|
|Special Qualities:||Blindsight 60 ft., Creeping, Ooze Traits, Undead Qualities|
|Saves:||Fort +4, Ref -2, Will -2|
|Abilities:||Str 10, Dex 3, Con 15, Int -, Wis 2, Cha 1|
|Environment:||Any land or underground|
|Alignment:||Always chaotic evil|
|Advancement:||7-12 HD (Huge); 13-18 HD (Gargantuan)|
The bone slime is a negatively-powered ooze which not only slays other creatures but then animates their bones by instinct later. The origins of this ooze are not as many believe, that more mundane oozes eat undead and therefore become creatures of undeath themselves. No; in actuality, bone slimes are born from the Negative Energy Plane itself. Every so often, the Negative Energy Plane, for lack of a better term, bursts. In this spot, an infinitesimally small hole appears on the Material Plane. Instead of sealing itself, the planar hole instead forms a scab. In this case, that scab is actually a bone slime. It has negative energy properties even though it is not undead.
Wherever the bone slime moves, the hole to the Negative Energy Plane moves with it; too small to see yet large enough to impart power to the slime. When the bone slime is finally defeated, the rupture to the Negative Energy Plane seals itself.
The bone slime's tactics are simple -- If it senses a creature, it attacks. If more than one creature is near, than the bone slime is just as likely to release a few skeletons before entering combat itself.
Cold (Ex): Any victim hit by the bone slime's slam attack suffers 1d6 points of cold damage in addition to the physical damage. This cold radiates forth from the bone slime's tiny negative singularity which hides inside it.
Engulf (Ex): Any Large or smaller opponent hit by a successful slam attack may be engulfed in the next round. Victims can forgo their attacks of opportunity and instead can make a DC 13 Reflex save to avoid being engulfed. Engulfed victims are subject to 1d6 cold damage each round and are considered to be grappled and trapped within the bone slime's body. The bone slime is free to make other slam attacks in subsequent rounds, but can engulf only one Medium creature per 3 HD, one Small creature per 2 HD, or one Large creature per 4 HD. If a victim dies while engulfed, it becomes a preferential skeleton (taking the place of the oldest one the bone slime currently possesses). This distinction means nothing, but rather is simply the way the bone slime operates.
Skeletons (Su): If confronted with multiple opponents, the bone slime expels 1d6 skeletons form its mass. These skeletons conform to the statistics of standard Medium skeletons (see the SRD) and attack any living thing in the area. If no living beings remain in the bone slime's blindsight range, the skeletons collapse into piles of bones, rusty armor and dented weaponry awaiting the bone slime to slide over and reabsorb them.
Creeping (Ex): The bone slime can climb any vertical surface and can hang from the underside of any horizontal surface as long as a third of its mass touches a vertical surface. It can pass through openings as small as a human hand.
Undead Qualities (Ex): Bone slimes share certain traits with undead. They are not subject to ability drain or energy drain, they are healed by negative energy (such as inflict spells), and they take damage from positive energy (such as cure spells).
None -- As an unintelligent ooze, the bone slime cannot even use treasure, much less desire its presence. The only treasure a party might after defeating a bone slime is that of its most recently-absorbed victims.
In Your Campaign Edit
When a bone slime is destroyed, the rupture to the Negative Energy Plane seals itself. But what if this was not always the case? Then the adventure really begins! A tiny pinprick of negative energy might always be at the same spot forever. The implications of direct access to this plane are far-reaching and quite dangerous. An undead creature could conceivably drink from the area as if it were a fueling station, healing damage literally as it was inflicted onto them if they stood in the right spot.
As the GM, feel free to have fun with this scenario. Maybe instead of healing a creature, the rupture's energy began to poison the land around it. Over the course of a few years, every plant and animal that dies within a mile of the rupture would rise as some kind of minor undead. This sounds like the perfect first exposure to undead for a low-level party. The objective is to locate the negative energy rupture, now enlarged into a visible phenomenon, and close it. This could be as simple as simple as exposing the rupture to positive energy or even striking it with a weapon.