Chameleon Technology

TARDISES

All Type 58 and later timeships (as well as TARDISes with the Mark IV upgrade) are designed to automatically scan the target area right before materialization and automatically select a disguise that will hide it. Since every piece of matter in the universe casts an image in the Vortex, a TARDIS can scan this image. During the first nano-second of materialization the TARDIS creates a 12 dimensional data map of everything within a thousand mile radius and determines which outer shell would best blend in with its environment. It then imprints this image on its exo-shell (or its infrastructure), allowing it to precisely duplicate the appearance of the nearby object. It is possible to use the manual override codes to select a different disguise. If a TARDIS is abandoned by its operator it will deactivate most of its systems, and alter its appearance as necessary to avoid attracting attention.

Chameleon Arches

The Chameleon Arch modifies the biology of an individual, essentially changing that individual's species. Connected to a TARDIS's databank via a cable, or integrated into a Time Ring, the arch incorporates a biodata module usually resembling a fob watch (though The Intern's disguised itself as a Galaga pin). The Biodata unit stores the Time Lord's essence and can return it to the Time Lord. It gives the Time Lord a new personality and memories. To ensure that the biodata module would not be noticed, it incorporates a perception filter preventing the user and others from seeing what it really is unless they are another Time Lord. Using the arch re-wrote a Time Lord's cellular biology and was therefore painful.

Some traits of the user's true Time Lord self still remain after the use of the Chameleon Arch. Destroying a Chameleon Arch while the user was not a Time Lord would render their Time Lord personality and biology irretrievable.