Preparing the next session of the Saga I run I've come up with a concept for a magical construct: An elemental-like iron maiden (as in en.wikipedia.org/wiki/Iron_maiden_%28torture%29). This magical construct was stolen from a magus that used it to interrogate people.
The magical construct has humanoid shape (size +1), its torso and abdomen are bent inwards. Its arms, when closed, form the “door” of the maiden. Torso and arms are full of piercing spikes. It also has strong legs that allow it to walk slowly to its victim.
Once activated by using a few Terram pawns, the construct has the ability to trap people inside. It delivers an Incapacitating wound if it catches a victim (with a successful grappling action). In addition, it uses Corpus vis to keep alive the victim (yuk! ). Lastly, it has the ability to talk with the victim trapped inside to retrieve the information desired by its master.
Now I face a doubt: Is it better to create the elemental-sarcophagus as a magical object or as a magical being (e.g. using an elemental as a base)? How would you create this construct?
Posing the silent question is just so much easier that I find somewhat odd that a device has a realistic purpose. I imagine that the creator might not have had sodalies that he could trust to interrogate for her (exceedingly common), and had a deficiency in mentem or intellego (not at all unheard of), or alternately she was just a sadistic cuss.
Well if you create it as a magical being then you have to be able to trust the being, and the being will know your secrets and it can be posing the silent questioned itself (well it doesn't have eyes but a wizard's boosted version would do it).
One option along these lines is the merinita mystery of animae magic, but assuming that you don't have that particular mystery here's a few thoughts on getting a spirit hooked in to your device:
First gain a few levels of magic lore and use them to find a spirit that can both control metal and that has a personality that isn't especially difficult.
Then find an arcane connection to the spirit and fix it.
Level 15 can summon a disembodied spirit
level 5 can control it
You are a magus with a permanent arcane connection to the target spirit, make it completely clear that in this situation what the spirit most wants ins to make you happy and what the spirit least wants is to arouse your ire, then encourage the spirit with both the rewards and threats/punishment, give the spirit excellent justification to be very grateful to you (this probably won't engender affection because of the gift but it does make it easier to win arguments with it).
You could go whole hog and include the arcane connection as part of the iron maiden then enchant the summoning and controlling spells into the device to call the spirit and force it to do the bidding of the items wielder whenever it is summoned.
From the enchanted device point of view you could enchant the item to move to your command base 10 Rego Herbam makes an object move with purpose and intelligence without requiring constant control. But this would be a device that has the IQ of a the dumbest of industrial robots.
A more impressive option is to enchant a constant duration creo mentem or creo animal effect that gives the iron maiden some sort of mind. Couple this with a rego terram to allow it to move on it's own and you've got the gizmo you want.
In either case I'd further enchant it with range touch rego mentem effects to force a trapped creature to truthfully and forthrightly answer any question asked of it. But then, if you can do that, why are you bothering with torture?
So this brings us to the option of a magical thing that just happens to be an iron maiden, Realms of Power Magic has rules for creating magical things as beings, I think they'd work. Perhaps the device was made by a master craftsman who had the touched by (realm) virtue and it was created out of exceptional materials and so it just awoke with an elemental spirit.
In the end I decided to create it as a Magical Thing (as per the Realms of Power: Magic rules) but I really liked the other options you mention.
Regarding the rationale for the horror movie-like gizmo... well. As you mention if a magus wants to obtain something he can just go for the posing the silent question spell and that would be easiest and more efficient but I was looking for something that, in addition, could scare other people without reverting to more magic.
This item was found by the characters whilst raiding a covenant banned by the tribunal. The purpose of the item is more “aesthetic” than “practical”. It was designed to show the players how evil was one of the magus of the covenant and how right were their peers to declare him marched.
Within the game, the item was used by the magus minions to obtain information from his mortal enemies. In this way the magus was not required to intervene in the interrogatory and, most importantly, word of the horror was passed to other potential enemies.
). Lastly, it has the ability to talk with the victim trapped inside to retrieve the information desired by its master.