Cascading biogenic pulse
From Memory Alpha, the free Star Trek reference.
A cascading biogenic pulse or thalaron generator[1] is a device which generates and emits thalaron radiation. Such a device can kill all biological life within its range. Thalaron radiation's massive destructive potential lead the Federation to consider it a biogenic weapon.
A small cascading biogenic pulse was used in 2379 by Shinzon to assassinate the Romulan Senate. Shinzon also had a larger, ship-mounted version of the pulse installed aboard the Scimitar, theoretically capable of killing the population of an entire planet. Both devices, when activated, opened much like a blooming flower.
In 2379, Shinzon intended to use his ship-mounted cascading biogenic pulse to kill everyone on Earth in a bid to conquer the Federation. Before he could set upon this task, he attempted to use the device to kill the crew of the USS Enterprise-E. His plot was thwarted when Lieutenant Commander Data fired a phaser directly into the pulse, destroying the Scimitar and himself to save his crew mates and Earth. (Star Trek Nemesis)
