[OOC] Return to the Rusty Rat

[Toot]

I will crosscheck the early conversation but I like the "believe" part providing a false feedforward to the tactile sensors. Conveninently, I can do so because the successful saves prevent this question from aborting the flow of things.
Behind the scenes, recently I've been trying to embrace the "flow with the story, ruling whatever makes sense" way instead of heavy rules-debates.

But there are spells that tick the mind into believing they are real.  But Silent Image doesn't happen to be one of those spell.  When someone tries to touch a silent image their hand goes right through the figment so they automatically know it's not real.  It isn't until the caster gets Shadow Conjuration (5th) does an arcane caster begin to be able to create objects that you can touch and do damage.

About the barrels being able to move with the heads; I guess the heads have to move for that, and Shanna has to react on that, fast enough, and precisely enough, but (funny as it sounds) she has to see through her own illusion in the first place to be able to do so (shouldn't be that hard but still there's a chance for failure).

The caster is the person creating the Silent image so she knows the silent image is fake so she can automatically see through the illusion.  As highlighted below, once you know it's an illusion you can automatically see through the image.

Saving Throws and Illusions (Disbelief ): Creatures encountering an illusion usually do not receive saving throws to recognize it as illusory until they study it carefully or interact with it in some fashion. For example, if a party encounters a section of illusory floor, the character in the lead would receive a saving throw if she stopped and studied the floor or if she probed the floor.

A successful saving throw against an illusion reveals it to be false, but a figment [Which is what a Silent Image is] or phantasm remains as a translucent outline. For example, a character making a successful saving throw against a figment of an illusory section of floor knows the "floor" isn't safe to walk on and can see what lies below (light permitting), but he or she can still note where the figment lies.

A failed saving throw indicates that a character fails to notice something is amiss. A character faced with proof that an illusion isn't real needs no saving throw. A character who falls through a section of illusory floor into a pit knows something is amiss, as does one who spends a few rounds poking at the same illusion. If any viewer successfully disbelieves an illusion and communicates this fact to others, each such viewer gains a saving throw with a +4 bonus.

That said, I guess these insects don't bite like mammals, hurling their heads forward. Rather, they use their mandibles in place... or something like that. But truth be told, I never thought about whether moving the objects could be done while it's not your round or not. What do you all think? Should it be immediate like speech, as part of concentration?

I believe that the caster's mind is quick enough to be able to anticipate most movements but I will do more research on this.