Shielded Flood carrier form
From Halopedia, the Halo wiki
Template:Ratings Template:Flood Species Infobox
Shielded Flood Carriers are a variant of Flood Carrier Forms with Jackal Point Defense Gauntlets. These were tested by Bungie and their unfinished forms have been found buried in the Halo 2 disc, but they have not been included in any actual game.[1] The behavior of the Shielded Carrier Form is identical to the unshielded variant, the sole difference being that it is harder to shoot them.[2] It is impossible that these forms are infected Jackals, because Jackals lack the amount of calcium needed to be infected.
Deleted Material
Shielded Flood Carriers are part of the Deleted Material cut from the Halo game.
When developing Halo 2, Bungie faced numerous delays for various technical reasons. The actual launch date of the game was almost a year after its original date (Just the E3 2003 Demo supposedly took 7 months to complete).
As such many aspects of the story such as vehicles, game play/design and story elements did not make it into the final version of Halo 2. Many of the elements have been by confirmed by such things as videos and commentary on the Limited Edition special DVD for Halo 2.
Trivia
Possibly because they are just an unfinished test, these Carrier Forms' "hands" pass through their shields freely.