TARDIS
From Multiversal Omnipedia
A TARDIS (which stands for Time And Relative Dimensions (or Dimension) In Space is a highly advanced time and space travel vehicle created by the Time Lords of Gallifrey. The most useful and striking element of a TARDIS is its size- through its transdimensional nature, it is far larger inside than it is outside. A TARDIS contains many rooms, and has more interior space than many mansions. This interior can be manipulated, rearranged, or even jettisoned as need or desire dictates.
Most of these rooms are unremarkable, but a few unique chambers bear noting. The console room (of which there may be two or more) contains the console, the complex and partially telepathic means of piloting the vehicle. (The console can also be used as a travel vehicle by itself, but this is risky- such an attempt sent the Third Doctor hurtling into a parallel universe.) The Zero Room contains an environment that can help a Time Lord recover from an unstable regeneration, or simply meditate. The Doctor's TARDIS also contains an access to the Eye of Harmony- whether this is common to all TARDISes is unknown.
The Doctor's TARDIS' model is Type 40, but this is a rather antiquated version. The Doctor's TARDIS also contains dressing rooms, hot water baths, a garden plaza he calls the Cloisters, bedrooms, a kitchen, and many other useful chambers. The vehicles are more or less immune to conventional weaponry (no matter their present form), but highly advanced or mass-destruction weapons may break through (such as that of the Time Lords and Cybermen, respectively).
The only normal access is protected by a key, which can be found in various forms. Very powerful or noncorporeal beings can gain access in certain situations. A TARDIS is somewhat sentient, having a sort of rapport with its pilot, and warning them of danger via the Cloisters' bells. It is also capable of changing its form to blend in with any environment via its chameleon circuit. (The Doctor's TARDIS' chameleon circuit is damaged, fixing it in the form of a police telephone box such as existed in the 1960s on Earth.) The default form resembles a simple blank cabinet with a door.
