Box
From Tardis Wiki, the free Doctor Who reference
Following a stopover in 1963 London, the Doctor's TARDIS was stuck with the exterior shape of a telephone box, specifically a police box, due to a malfunction in its chameleon circuit. (TV: "The Cave of Skulls") As the First Doctor explained to Ian Chesterton and Barbara Wright, the box was an entrance chamber to a fourth dimension, leading directly into the control room. (COMIC: The Secrets of the Tardis)