The Monk's TARDIS

The Monk's TARDIS was a Mark IV TARDIS owned by the Meddling Monk.

History
Unlike the First Doctor's TARDIS, at this time the Monk's TARDIS had a functional chameleon circuit and directional unit. After visiting several moments in Earth history, he landed in Northumbria in 1066 and disguised his ship as a stone sarcophagus in his monastery. The Doctor learned of the Monk's plans to change history and sabotaged his TARDIS, making it the same size inside as outside. This made it impossible for the Monk to get inside it. (DW: The Time Meddler)

The Monk eventually fixed the dimensional controls. On a later adventure on the volcano planet Tigus, Mortimus's ship turned into a large rock. Meeting again in ancient Egypt, the First Doctor changed it into a police box so Mavic Chen and the Daleks would mistake it for the Doctor's TARDIS. He also stole the Monk's directional unit so the Monk would re-materialise in a random location. The Monk ended up in an frigid planet with his TARDIS disguised as a block of ice. (DW: The Daleks' Master Plan).

When the Fifth Doctor next encountered the Monk, he had voluntarily re-configured his TARDIS into a police box. The Monk had the top of his ship's roof blown off by Ice Warriors with a sonic cannon. (DWM: 4-Dimensional Vistas)

The Seventh Doctor met the Monk in London in 1976. Mortimus, posing as a record executive, had turned his ship into a desk, complete with scraps of paper. The papers retained some of the special qualities of his TARDIS, allowing the Doctor to use them to return to Earth after the Monk vengefully tried to abandon him on the same icy planet where he had been trapped. (NA: No Future)

The Eighth Doctor, along with his new companion Tamsin Drew had a reunion with the Monk in the Abbey of Kells, Ireland in the year 1006. Under the alias of Abbot Thelonius, the Monk used the impressive artistic skills of the monks to draw a new directional circuit for his TARDIS, using a page of the Book of Kells and liquid Gallifrite. Unknown to the Monk, Tamsin had switched his circuit for a false one, prior to the first test of the circuit and again the Monk's TARDIS was crippled. However, the Monk was able to rectify this and had several more meetings with the Doctor. (BFA: The Book of Kells)