Coordinated Stage

The Coordinated Stage is the second stage of a Flood infestation. During this stage, Flood population begins to rapidly increase, and, once sufficient biomass has been found, Pure Forms begin to be sent into combat. After this the next stage of Flood infection may begin. Note that this part of Flood evolution can only be reached once a viable Gravemind takes form. During this stage, all Flood can communicate with thoughts and attack strategically.

Trivia
this is the stage that happened during Halo 2.