Son: "But dad I don't want to wait in The Flood."
You mean the flood? Yeah that place is becoming more like /b/ everyday. You know... without the kiddie porn
Bystander: "The Flood!"
2) The "weapon" in Halo that The Covenant was in desperate search of acquiring in order to wipe out mankind (NOTE the similarity between this and definition 1.) The Flood itself, is actually a humanoid, body-snatching race of fungal origin and consists of 4 subtype species. Can easily be n00bed via shotgun.
"I just n00bed 3 flood with one shotgun blast."
"the flood will destroy /b/ in the course of next year"