The room of truth is how it's called an arcane construct of a chaos-loving archmage called Zarathustra, it is, or rather it was, a marble building, made out of 6 big panels which formed a cube, in it's side, inside, top and bottom were handwritten by Zarathustra itself a million runes which formed the rules of it.
The room can take any form, be of any size, be of any time, also it appears where chaos will cause the most destruction be it mental or physical, and leaves when creating more chaos will cause the existing to be normal, the main spell of the room is that, ANYTHING said inside it WILL be true, the only exception are statements which causes mental changes, mental changes happen slowly at a speed which the person who is affected will most likely not notice, unless it's a very knowledgeable person in which case can undergo a challenge to make his mind back to normal. The room can also change reality to satisfy a statement said inside it, but, like mental changes it happens at a pace the affected will not notice. The Room also has an "aura" of impulse to people inside and for the people outside it's very attractive, meaning that people are "attracted" to the room, exactly like a glamour, and inside it, they tend to be more impulsive and say things without much thought. The room act as a "bad-genie" for statements, that's where the chaos part comes in. It has been disguised as many things, as an university corridor, a prison death-corridor, an AA meeting room, an abandoned buildings where punks hang out, a library where teenager roleplay, and in some rare cases a troubled teenager room.
Zarathustra still lives today and is said to always be in watch of the room wherever, whenever it is, will be, has been.
Another is that the room favors affecting teenagers over adults,as they tend to cause the greater amount of chaos than their parents, as so said Zarathustra.