Brilliant Gift
From Halopedia, the Halo wiki
The Brilliant Gift is a Covenant Spirit dropship seen crashed in the swamps in 343 Guilty Spark, later used by the Flood to board the Infinite Succor.
It is to be noted that the Flood were infected Human Combat forms armed with human weapons and NOT Covenant. They were possibly members of Captain Keyes' team when they first encountered the Flood.
The dropship crashed onto the Infinite Succor's hanger and was irreparably damaged. However, it did not matter. The Flood soon spread throughout the Infinite Succor, infecting the entire crew and the creatures in the hunting ground except the Legate.