Updating antique ice box
Once a time machine is properly primed, however, with the imprint stored on a device called a "briode nebuliser", it can be used safely by any species.According to Time Lord law, unauthorised use of a TARDIS carries "only one penalty", implied to be death ("The Invasion of Time", 1978).
They are also said to draw power from the entire universe as revealed in the episode "Rise of the Cybermen" (2006), in which the TARDIS is brought to a parallel universe and cannot function without the use of a crystal power source from within the TARDIS, charged by the Doctor's life force.
This was referenced on-screen in the episode "Blink" (2007), when the character Detective Inspector Shipton says the TARDIS "isn't a real [police box].
The phone's just a dummy, and the windows are the wrong size." The production team conceived of the TARDIS travelling by dematerialising at one point and rematerialising elsewhere, although sometimes in the series it is shown also to be capable of conventional space travel.
Within the context of the series, the Doctor's TARDIS has a faulty chameleon circuit that keeps it permanently stuck in the police box form.
Despite being shown several times trying to repair it, the Doctor claims to have given up the attempt as he has grown accustomed to its appearance. In the first episode, "An Unearthly Child" (1963), the TARDIS is first seen in a 1963 junkyard.