Headhunters (Team)
From Halopedia, the Halo wiki
Headhunters are Spartan-III Special Operations squads comprised of two man teams that are sent on suicide mission to attack high priority Covenant targets. Headhunters are tasked to infiltrate heavily fortified enemy encampments, ships, and operation centers completely undetected, with minimal, mission-specific weaponry, and no radio contact or hope for backup or retrieval. Headhunters are normally sent in as preparation for one of two eventualities: a larger, full-scale assault on the target, or as a decoy and distraction for UNSC operations elsewhere.
A number of these teams particpated in a mission on an unnamed Covenant moon.