Confession Dial
From Tardis Wiki, the free Doctor Who reference
The confession dial was a device containing the last will and testament of a Time Lord.
After being summoned by Davros, the Twelfth Doctor left a confession dial with Ohila for her to deliver to Missy. (WC: Prologue) After receiving the dial, Missy brought it to Earth and deliberately attracted UNIT's attention. When she met with Clara Oswald, Missy explained that the confession dial was to be given to a Time Lord's best friend prior to their death. Clara then attempted to pick the dial up, believing Missy delivered it to her on the Doctor's behalf. The dial responded by shocking Clara, leading Missy to explain the confession was for herself, and would only open after the Doctor died. (TV: The Magician's Apprentice)
