Incorporeality is, in many ways, the exact opposite of invisibility. You usually can see the creature just fine, but the creature has no physical substance. If you attack it, or try to touch it, nothing seems to be there.
The Basics of Incorporeality
An incorporeal creature has the incorporeal subtype, which is described in detail in the Monster Manual glossary (and updated in the Monster Manual III glossary). As with many things in the D&D game, incorporeality is actually pretty straightforward. Figuring out how incorporeal things interact with the rest of the game world gets difficult, though. Take a look at this quick summary of what the Monster Manual has to say about incorporeal creatures.
No matter what the creature looks like, it has no flesh, bones, protoplasm, or any other substance that makes up a corporeal creature's body. In effect, an incorporeal creature is a disembodied intellect or spirit.
Because it lacks a physical body, it has no Strength score. Theoretically, an incorporeal creature may have a Constitution score, but such a creature would be strange indeed. In any case, incorporeal creatures don't need to eat, drink, or breathe. In fact, they cannot do these things because they have no Strength scores and they can't affect physical objects (or even air).
Most incorporeal creatures cannot benefit from magical effects that require physical contact or manipulation of objects. They cannot benefit from bull's strength spells (they have no Strength scores to enhance), potions or oils (they cannot drink potions or apply oils), wear rings, don armor (except for ghost touch armor), or wield weapons (except for ghost touch weapons) or any other magic items that have to be worn or held to be used (which is most of them).
Some items, such as ghost touch weaponry, work for incorporeal creatures. In such cases, an item that an incorporeal creature carries or hold also is incorporeal until the incorporeal creature, drops it, throws it, or puts it down (but see the section on ghost touch weapons).
Incorporeal creatures are weightless. They cannot fall or take falling damage. The rules say incorporeal creatures cannot trigger traps that are activated by weight (such as covered pits). Though the rules don't say so specifically, an incorporeal creature won't trigger any trap that has a purely mechanical trigger.
Incorporeal creatures move by flying, and they have perfect maneuverability.
Presumably, an incorporeal creature can make some noise if it wants to -- perhaps a series of eerie moans, rattles, or taps.
Because it has no body, an incorporeal creature also has no scent and doesn't create any tremors in the ground or any currents in the air. Special qualities such as tremorsense, blindsense, and blindsight usually don't allow their users to discern incorporeal creatures.
Without a physical body, most attacks simply have nothing to hit or to affect. A magical attack (including a magic weapon) made by a corporeal creature has a 50% chance to fail (with some exceptions). This reflects the possibility that the magic can somehow reach the creature and affect it. The failure chance works the same way as a miss chance does; for the sake the convenience, most people refer to the failure chance as the incorporeal miss chance.
See Incorporeal Creatures in Combat for a more detailed discussion of what works against them and what does not.
An incorporeal creature cannot pass entirely through an object that is thicker than its own space. For example, a spectre's size is Medium, so it can't pass through an object more than 5 feet thick. Without this rule, an incorporeal creature could use large solid objects to traverse great distances or even travel straight though the planet. The rules are silent on exactly how small an opening an incorporeal creature can pass through when an object is too thick to allow the creature to just move through it. I recommend that you allow an incorporeal creature to pass through any opening big enough to admit its head (if it has one). As a rule of thumb, this is about one eighth as wide as the creature is long or tall.
Incorporeal creatures can, and often do, use solid objects or even corporeal creatures as cover in combat; see Incorporeal Creatures in Combat for details.
In any case, incorporeal creatures ignore most things that hamper movement.
Because water isn't solid, it doesn't block or restrict incorporeal creatures at all.
An incorporeal creature doesn't lose its way when passing through a solid object, and its movement is not slowed when it cannot see.
Incorporeal Creatures in Combat
Handling a combat with a creature that is present on the battlefield but has no body isn't always easy, but it can be done.
Incorporeal Creatures Attacking
Most incorporeal creatures can deliver a physical attack by striking at other creatures. Although this attack is called an incorporeal touch attack, it more closely resembles a slam attack. It's called an incorporeal touch attack because it ignores armor, natural armor, and shield bonuses, just as a touch attack does. Unlike a touch attack, however, force effects block an incorporeal touch attack. Deflection bonuses work against incorporeal touch attacks (just as they work against true touch attacks). In most cases, you can resolve the attack using the defender's touch Armor Class -- just be sure to include any force effects the defender is using, such as a mage armor spell (or a magic item that duplicates that spell's effects, such as bracers of armor) or a shield spell. Ghost touch armor also proves effective against an incorporeal touch attack.
Because an incorporeal creature has no Strength score, it uses its Dexterity modifier for melee attacks.
Because an incorporeal creature cannot exert any Strength and its body (such as it is) passes through material objects, an incorporeal creature cannot use bull rush, disarm, grapple, overrun, sunder, or trip attacks against corporeal creatures or objects. Some of these attack forms are possible against other incorporeal creatures (see Incorporeal Against Incorporeal in Part Four).
If an incorporeal creature can cast spells or use other kinds of magic, its spells and magical effects work equally well on both corporeal and incorporeal recipients (no miss chance), except that an incorporeal creature cannot touch a corporeal creature and cannot use spells or other effects with a touch range. Nevertheless, some incorporeal creatures have special attacks that can be delivered through its incorporeal touch attack, such as a spectre's energy drain attack.
Ghost Touch Weaponry
An incorporeal creature can pick up and wield a ghost touch weapon even though the creature lacks a Strength score. When the creature makes an attack, it uses its Dexterity modifier to modify the attack roll (even for a melee attack) and no Strength modifier applies to the damage roll. (Because the incorporeal attacker does not have a Strength score, its Strength modifier is +0.)
According to the Dungeon Master's Guide, a ghost touch weapon functions as either a corporeal or incorporeal object, whichever is better for the wielder at the time. This is convenient for an incorporeal creature that wants to carry a ghost touch weapon through a wall. What this means when an incorporeal wielder uses a ghost touch weapon to attack a corporeal foe is not quite clear, though. Presumably, an incorporeal wielder can choose which way the weapon acts at the time of the attack; this does not require an action on the wielder's part, and the wielder can make the choice even when it is not the wielder's turn. (For example, when the wielder uses the ghost touch weapon for an attack of opportunity.)
When an incorporeal attacker wields a ghost touch weapon as a corporeal weapon, the attack is resolved against the defender's normal Armor Class. An incorporeal attacker wielding a ghost touch weapon in this manner can use the weapon to make a disarm or sunder attack. If the weapon can be used for a trip attack (see the weapon's description in Chapter 7 of the Player's Handbook), an incorporeal attacker can make a trip attack with it.
When an incorporeal attacker wields a ghost touchweapon as an incorporeal weapon, the attack is resolved as an incorporeal touch attack. If the attack hits, the weapon deals the normal damage for a weapon of its kind, plus any bonus damage from its enhancement bonus, but no Strength modifier applies. If an incorporeal creature fires ghost touch ammunition or throws a ghost touch weapon, the projectile or weapon becomes corporeal the moment it leaves the incorporeal creature's possession, though it retains the ghost touch property.
The foregoing suggests that a corporeal attacker could choose to wield a ghost touch weapon as either a corporeal or an incorporeal weapon as well, but I don't recommend that you do so. The ghost touch property isn't priced to reflect such a potent ability. If you don't like the disparity in abilities between corporeal and incorporeal wielders, I recommend that you always have attackers use ghost touchweaponry as a corporeal attack (except that the weapon still ignores incorporeal miss chances).
That's all we have time for this week. Next week we'll continue our look at incorporeal creatures in combat.
About the Author
Skip Williams keeps busy with freelance projects for several different game companies and was the Sage of Dragon Magazine for many years. Skip is a co-designer of the D&D 3rd Edition game and the chief architect of the Monster Manual. When not devising swift and cruel deaths for player characters, Skip putters in his kitchen or garden (rabbits and deer are not Skip's friends) or works on repairing and improving the century-old farmhouse that he shares with his wife, Penny, and a growing menagerie of pets.
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