The Mutation Device was a machine used by Daleks in the early Last Great Time War. They intended to use it to corrupt the Minyan race bank, ensuring that the new race of Minyans would be instinctively loyal to the Daleks instead of siding with the Time Lords in the War as they otherwise would have done. The Daleks managed to plant the Device on New Minyos, but the Fourth Doctor deactivated it using his sonic screwdriver after Leela made the Dalek party destroy each other. (GAME: Lost in Time)