DM-3-1123 b
From Halopedia, the Halo wiki
DM-3-1123 b[1] was a planet in the DM-3-1123 System and had a population of approximately 1.3 billion Forerunner beings.
A Forerunner naval group engaged a Flood irregular naval group of 149 non-military vessels over DM-3-1123 b, destroying the contaminated vessels. But the Flood's sole intention was to infest the planet, and within 32 hours, they had overrun local Forerunner ground forces, and only 0.0006% of the planetary population was evacuated before the Forerunner local fleet-- upon an 83% consensus-- launched a "blanket orbital bombardment" on DM-3-1123 b, destroying the Flood infestation but rendering the planet uninhabitable and sacrificing much of the planetary population.
