Black hole converter
From Tardis Wiki, the free Doctor Who reference
The Master placed a black hole converter on each of his warships. They were intended to destroy other planets once the Time Lord Empire launched its war against the Universe. When he lost control of Earth, he told the Doctor he would rather destroy it, but was talked out of it by the Tenth Doctor. When time was reversed, the warships and black hole converter. (DW: Last of the Time Lords)
