Cost: 80 points

Insubstantiality is an exotic Mental/Physical advantage (B62)

Possession has a Spiritual limitation when it involves an insubstantial body inhabiting a possessed one.


GURPS Powers 55 clarifies a major difference with insubstantiality as it appeared in Spirit Form (Spirits):

Paradoxically, most such entities can “anchor” themselves to material objects as needed, allowing them to stand on floors, ride in vehicles, and so on. This is a standard feature of Insubstantiality.

It did not clarify how to deal with those unable to anchor to material objects though, or whether living vehicles (ie horses) could be considered material objects.

P56 expands on different types:

  • Dimensional
  • Divine
  • Elemental
  • Magical, Psionic or Spirit


Injury Tolerance (Diffuse) might let Talent aid resistance rolls against Affliction (Advantage, Insubstantiality)


see Other Dimensions and Supernatural Beings regarding Projection



pg 42:

The first level of Vulnerability allows the attack to affect

the spirit in its spirit form

If the Vulnerability affects the spirit only when it is materialized, the total value is halved.

This how iron worked for the Fairies, in GURPS Fantasy this was replaced with giving them the Illusory limitation so that all physical attacks hit them for half damage, so iron ended up doing x1.5 instead of +2d6



2012 in Tuoni posted:

going the modified Insubstantiability route creates vulnerabilities that might not be realized until after play begins.
Such as the fact that the insubstantial character can be grappled by other insubstantial beings (ghosts)

This is not 100% true. It is probably based on this part from B63:

Your physical and energy attacks affect other beings using the same form of Insubstantiality, and their attacks affect you.

So to affect those using DIFFERENT forms...

  1. take "Affects Substantial" for Insubstantiality
  2. do the Limited Enhancements of "Affects Insubstantial" reduced by Only While Insubstantial and Insubstantial Only]" on an attack.

Or for punches/grappling/shoving ala the Subway Ghost in the 1990 film Ghost, you would do this for Modifying ST-Based Damage / Modifying Existing Damage

In the alternative, taking the Substantial Only limitation on Insubstantiality could be interpreted as meaning you aren't insubstantial relative to ALL other insubstantial beings, not just your own type.

  • They could still be to you, 1-sided unless you both have the limitation) similar to how you can take that on Invisibility so that insubstantial beings can see you without needing See Invisible.

2007 discussionEdit involves comparing Insubstantiality with Altered Form which endows Always-On Insubstantiality.

What they neglect to consider is that the 90% cost version of Alternate Form requires a way to change people back against their will which Insubstantiality normally doesn't have, so the difference in cost is not as big as they would think. It would be 100% of the 50% cost, not 90% of the 50%

This also requires the +50% Once On, Stays On enhancement for the basic cost.

2017 discussion on anchoringEdit

archived here, this discussion was hidden from view by moderators due to a dislike of the thread creator, resulting in the hiding of replies by others:


I'd call it Accessibility at a low value for "Can't catch a bus." Unless your campaign involves insubstantial beings needing to move long distances, it's rarely going to be more than -5%.


Well, you're still anchored to something or else your position becomes dissociated with the planet.


Which is why it's a default feature. Yeah I'd call can't move along with something that could carry you in reality a (fairly tiny) limitation, -5% seems fair.
Any time you find yourself starting to think about the physics to Insubstantial, you should probably stop. The purpose of the advantage is "walk through stuff". Interpretations that let you fly at high speeds, fall into the center of the earth, be unable to move, fly off into space, bypass armor, damage things by reaching into them, turn invisible, have you end up naked, or really even become invulnerable though that one is unfortunately baked into the GURPS description, should be rethought. You can price many of them as limitations or separate traits if you really have to include them, but generally you don't need too, because the kinds of stories that use insubstantiality don't bother.
It's not and never will even vaguely realistic, so efforts to pretend it is and work out logical consequences are just missing the point.

Rainbow Factory:

The powers book has this optional modifier for Always on.
Usually On: Any advantage that can be Always On can instead be Usually On. The ability is on almost all the time – but the user can switch it off briefly by expending 1 FP per second. If Always On is no worse than -20%, Usually On is worth half as much; if it’s a larger limitation, add a +10% enhancement to find the value of Usually On.


Chronos from “Bearing an Hourglass” and an alternate reality version of Kitty Pryde from the X-Men have both used a form of this limitation on their insubstantiality as a pseudo-teleporation ability, detaching from one of the anchored vectors for a time and letting objects (Earth) slide around them. Kitty had very little control and used it as an emergency escape.


If that is the only way you can do it and there isn't anyway to rescue you it is equivalent to an instant suicide ability and probably should just be a perk. had examples:

  • Spirit Projection "Missing Powers: cannot taste/smell, or ride in vehicles"
  • Genius Loci: "Missing Powers: cannot taste/smell, or ride in vehicles"

GURPS Spirits also had examples

  • pg 50 Apparition "Can’t Materialize: sounds, visual, and ectoplasm effects only -5%, can’t ride in vehicles"
  • pg 55 Zar "Can’t Materialize -20%, Can’t ride in vehicles" (this proves you still got the -5% discount when you were forced to purchase it by an inability to materialize
  • note that on page 51, the Ascended Spirit had "Can’t Materialize: sounds and visual effects only -10%" without taking the -5% for an inability to ride vehicles, so they presumably could and it was only mandatory for the -20% version

see alsoEdit