Epitaph stone
From Tardis Wiki, the free Doctor Who reference
Epitaph Stones were a method of communication used by the Shansheeth. They were small shards of black stone which produced holographic messages, allowing the Shansheeth give their condolences. The Claw Shansheeth of the 15th Funeral Fleet used a epitaph stone when contacting Sarah Jane Smith on the "death" of the Doctor. (SJA: Death of the Doctor)
