Psilent Songbox

From Tardis Wiki, the free Doctor Who reference

The Psilent Songbox of Karn was an augmented Gallifreyan children's toy. (COMIC: Kill God) The War Doctor, the Master, and The Squire stole the Songbox during the Last Great Time War to help them defeat the Cyclors.

Alice Obiefune stole the Songbox from the Doctor and used it herself, banishing the Cyclors to a higher dimension. After the Master attempted to escape by flying a TARDIS from his future, the paradox that was created reacted with the Songbox, collapsing timelines together, resulting in complete chronal meltdown. (COMIC: Kill God)