Fantasy Trip Illusions

[Keysh]

After having reviewed the discussion of Illusions in In the Labyrinth (esp. pp.138-139 of the current PDF draft), I think some of the confusion can be avoided by paying attention to a couple of things:

1. Illusions (of animate beings) cannot affect inanimate objects, nor can they affect organisms with IQ or 0 or 1 (such as slimes and plants).

p.139: "An illusion cannot affect any inanimate object; its effects are wholly mental, and are the product of the wizard’s mind and the minds of those who see the illusion."

"Since an illusion cannot affect an inanimate object, it can never open doors, fetch drinks, spring traps, etc."

p.138: "a being with an IQ of 0 or 1 (which includes plants and most kinds of slime) has so little mind that it cannot be fooled. Thus, it cannot see the illusion and cannot affect or be affected by it."

2. (Almost all) Illusions of inanimate objects are intangible.

p.139: "At any rate, most inanimate illusions are quite intangible. (If you come to an illusion of a bridge, your foot will go right through it (though the bridge won’t vanish until you disbelieve). An illusion of a flying carpet won’t take you anywhere. And so on." [emphasis added]

So:
You cannot walk across an illusory bridge, and an illusory lid or board will not stop a torch from falling into a barrel of gunpowder.

Similarly, illusory cats will not mess up litterboxes (let alone leave behind illusory evidence of their presence). A real cat will find its urination goes right through an illusory litterbox, leaving behind a puddle on the floor (and if there's a slope, you might notice the urine running downhill out from under the Illusion of the litterbox).

Could an illusory person/animal/monster push their way through a crowd of people, or a herd of sheep? Yes. Could it push its way through heavy undergrowth? No.

Rather than complaining that these represent defects in the perfection of an Illusion, I think a better approach is to realize that this is one of the limitations of Illusions: sometimes they behave in such a way as to reveal that they are Illusions. (Most obviously, if your foot goes through an illusory bridge!)