The Moment

The Moment was the doomsday device that the Doctor used to facilitate the end of the Last Great Time War. (DW: The End of Time)

The Eighth Doctor created the Moment from a modified De-mat Gun during the War. The Doctor used the Moment to end the war, time-locking it in the process. When the Doctor used the Moment, he destroyed Gallifrey, the Cruciform, the invading Dalek forces, the Time Lords, and all the horrific entities created during the Time War. (IDW: The Forgotten, Don't Step on the Grass)

The Ninth Doctor once stated that all the combatants of the Time War had burned and been "wiped out in one second". (DW: Dalek)