Outer plasmic shell

The outer plasmic shell, which has dimensionally transcendental properties, alters as the exterior of the TARDIS changes shape. The real world interface on the outer plasmic shell enables users to enter or leave the ship. With models such as the Doctor's TARDIS, a Type 40 TARDIS, the outer plasmic shell responded to a chameleon circuit. (DW: Logopolis)


 * Later, more sentient TARDISes might decide what to change into all by themselves. We do not know if the outer plasmic shell of a TARDIS could also change into other solid form, i.e. liquid or gaseous.