GURPS Powers 55 expands on different types:
- Magical, Psionic or Spirit
- Injury Tolerance (Diffuse) might let Talent aid resistance rolls against Affliction (Advantage, Insubstantiality)
- 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 http://forums.sjgames.com/showthread.php?t=93942 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...
- take "Affects Substantial" for Insubstantiality
- do the Limited Enhancements of "Affects Insubstantial" reduced by Only While Insubstantial and Insubstantial Only]" on an attack.
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.