Ended does this to end the war with the bugger:

Ender quickly assigns his squadron leaders to take control of their few ships and shape them into a cylinder, pointing toward the planet. As the enemy formation closes in on them, Ender's fleet melts "into chaos," with his ships firing at any and all of the enemy ships and getting cut up themselves. After a few minutes of this feint, Ender organizes twelve remaining ships into a formation about halfway to the planet. At Ender's command, the ships drop straight toward the enemy's planet to use the M.D. Devices. At least one Little Doctor reaches the planet with its effects, because the planet suddenly begins to bubble, and within three seconds "the entire planet burst apart, becoming a sphere of bright dust, hurtling outward." Only the starships on the outer edge of the battle survive, including just two or three of the enemy ships. Gravity starts pulling the debris from the explosion back together.