Cyber-megatron bomb
From Tardis Wiki, the free Doctor Who reference
A Cyber-megatron bomb was a cyber-bomb which Cybermen tried to use during an invasion of Earth in the second half of the 20th century.
It was able to destroy life on the planet completely.
It wasn't used because UNIT deactivated the radio transmitter which would have delivered it from the fleet to the planet. (TV: The Invasion)
