The Cradle (Death of the Doctor)
From Tardis Wiki, the free Doctor Who reference
The Cradle (Death of the Doctor) was a musical instrument and memory device used by the Claw Shansheeth. It appeared as an alien harp. While it was played, it induced memories, collected them, and gauged their strength. The effect could be strengthened to induce sleep. It could create holographic views of collected memories or show visuals those affected.
The Cradle was used in conjunction with the memory weave.