Tremulator
From Tardis Wiki, the free Doctor Who reference
The tremulator was a component of the Doctor's TARDIS. While the First Doctor was visiting the planet Demeter with his grandchildren John and Gillian, that world was attacked by robots on Bellus. Returning to the TARDIS, the Doctor activated the tremulator, which deflected the destructive waves from Bellus back to that planet, destroying it. (COMIC: The Ordeals of Demeter [+]Loading...["The Ordeals of Demeter (comic story)"])
