Variant Rule: Haunting Presences
Sometimes when undead are created, they come into being without a physical form and are merely presences of malign evil. Haunting presences can occur either spontaneously (see Atrocity Calls to Unlife) or as a result of the spell haunt shift. Tied to particular locations or objects, these beings may reveal their unquiet natures only indirectly, at least at first.
As a haunting presence, an undead is impossible to affect or even directly sense. A haunting presence is more fleeting than undead that appear as incorporeal ghosts or wraiths, or even those undead enterprising enough to range the Ethereal Plane. In fact, a haunting presence is tied to an object or location, and only upon the destruction of the object or location is it dispelled. However, despite having no physicality, each haunting presence still possesses the identity of a specific kind of undead. For instance, one haunting presence may be similar to a vampire, while another is more like a wraith.
The Haunting: Whenever an undead appears as a haunting presence, it haunts an unattended, mundane object or location. Using the same decision-making process that he uses to populate a location or area with a standard monster, the DM simply chooses an unattended mundane object or location as the subject of a haunting presence. The DM also determines the variety of undead (skeleton, zombie, wraith, or other kind) that serves as the source of the haunting presence. An undead may haunt a discrete object of at least Tiny size and no larger than Huge size. Items (both magical and mundane) currently in the possession of a character (often referred to as attended items) cannot be haunted. Unattended magic items receive a saving throw as if a spell was being cast upon the item (DC 10 + 1/2 the undead's HD + the undead's Cha modifier).
A haunting presence becomes a part of the object or location haunted. Haunting presences are always aware of what is going on around the object that they haunt. They can see and hear up to 60 feet away (but do not gain blindsight). A haunting presence cannot be turned, rebuked, or destroyed while the presence remains immaterial (but see Exorcising a Haunting Presence, below). Normal vulnerabilities of a particular kind of undead do not apply to the haunting presence of that undead. For instance, the haunting presence of a vampire haunting a fire poker is not destroyed if brought into sunlight.
Effects of a Haunting: A presence haunting an object may do so in a couple of ways. Undead of fewer than 5 Hit Dice may use only one form of haunting, but undead of 5 or more HD can make their presence known using either of the methods described below (impermanent home or poltergeist). No matter the way the haunting presence makes itself felt, the haunting presence of a sentient undead can always choose to speak to nearby creatures, usually in a whispery or incoherent voice that seems to come from the air. However, haunting presences are usually not much for conversation. Characters may note at times that the object they've found or the location they inhabit has a strange air, or the appearance of it is somehow "off" (with a successful DC 15 Intelligence check).
Impermanent Home: An undead presence haunting an object or an area can sometimes become more than a presence, actually taking corporeal or incorporeal form a number of times per week equal to the undead's Hit Dice (that includes haunting presences that manifest "physically" as incorporeal undead). The presence that takes form does so anywhere within the location it haunts, or in the closest empty space adjacent to the object it haunts. A presence that takes form can remain so for up to a number of minutes equal to its H D. An undead that takes form can always choose to return to its haunting presence status earlier, but it must take a move action to do so.
While in physical form, the undead can take any actions normal for an undead of its kind. It can attack, take damage, and even be destroyed. Unless it is a ghost, lich, or some other sort of undead that is resistant to destruction, the haunting presence is also permanently eradicated, though most attempt to return to their haunting presence status if threatened with such destruction.
Poltergeist: If an object has parts that move, such as a wagon, a clock, or a crossbow, a haunting presence can control the object's movement, though the object will move no faster than the undead itself could move in its normal form. Thus, a wagon can be made to steer toward a pedestrian on a street or roll out of a stable with no horse pulling it. A clock can slow or run backward. A crossbow can cock and fire (but not aim or load itself).
An undead with at least 10 HD and a Charisma score of 17 or higher can actually force an object with no moving parts to animate (see Animated Objects, page 13 of the Monster Manual), based on the object's size. No undead, no matter how many Hit Dice it has or what its Charisma score is, can animate an object that has a higher Challenge Rating than its own.
If a location instead of an object is haunted, the haunting presence can animate a number of objects equal to its HD at one time.
Exorcising a Haunting Presence: No matter how a haunting presence chooses to reveal itself, it is subject to being is covered and destroyed. Unfortunately, a cleric's turning ability generally has no direct effect on haunting presences, other than to irritate them and focus their attention on the cleric doing the turning. Something more is called for - an exorcist. Exorcism is a special ritual, involving a spoken formula calling upon one or more deities, used with the intention of driving out haunting presences. Exorcism of a haunting presence is essentially a two-step process - forcing a presence to become physical, then destroying the revealed undead in the most expeditious manner possible.
First, the forced revelation can be achieved through the use of a special ritual, which is generally known to anyone with ranks in Knowledge (religion). It must be performed by an exorcist who spends ten consecutive full-round actions chanting or speaking the formula that pertains to exorcism, at the end of which time the exorcist must make a DC 20 Knowledge (religion) check. If the exorcist's concentration is interrupted, the ritual must begin again. If the ritual is successful, the haunting presence becomes physical and must remain so for 1 full round. The exorcist's next action can be used to either attempt to turn the revealed undead, or to continue the ritual, with an additional DC 20 Knowledge (religion) check required at the end of each round. Each successful check forces the undead to stay corporeal or incorporeal for 1 additional round.
Even undead of 5 or fewer HD that normally haunt only as poltergeists are forced to take form by the exorcism ritual, as well as haunting presences that have already used up all their chances to take form for the week. Undead forced to take form usually use their actions to attempt to slay the exorcist before they themselves are destroyed, so exorcists generally bring along companions who can physically attack the revealed undead.