Flood transport form
From Halopedia, the Halo wiki
The Flood Transport Form, also known as the Sweeper, was a Flood Pure Form. Unlike the Carrier Form, which carries and incubates Infection Forms, the transport would carry a maximum of six unarmed Combat Forms to a particular destination.
Physical Description & Physiology
The sweeper would have had four triple-jointed limbs to move its load of troops around, and featured numerous tentacles to consume or recycle biomass, dead or alive. The sweeper also boasted a biomass re-processor that converted recently-consumed biomass into rapid-growth embryos or Combat Forms.
Before the Sweeper, or Transport Form, released its cargo, it would pass four steps, specifically: