Unique Enemies in Halo:
- Halo: Combat Evolved:
- In "343 Guilty Spark" you encounter a Marine driven insane by the (then-unencountered) Flood who will slowly shoot at the Chief when approached. His shots are too slow to do any real damage, and he can be left alone or killed with no consequence.
- "Two Betrayals" features Grunt Majors using Fuel Rod Guns. These particular enemies also have a unique model in Anniversary, confirming that they are a different entity from standard Grunt Major. They only appear a handful of times in "Two Betrayals", and nowhere else.
- At the beginning of "Keyes", a Grunt is chased by a harmless Flood Elite Combat Form whose limbs and head are all missing. This is the only Combat Form in the game whose extremities are already severed.
- Much later in "Keyes", just before reaching the Captain, a single Hunter will burst out of a side-room to attack a group of Flood. This is the only Hunter in the entire game that is not in a pair.
- In the final level, "The Maw" you can encounter the only group of cloaked Flood Combat Forms in the game. They only appear if you wait around for too long inside the armory.
- Also in the final level, there is a single Flood Combat Form in the last hallway before the engine room that is allied with the Covenant.
- Halo 2:
- "Cairo Station" has a pair of Elites dual-wielding plasma pistols at the beginning, an uncloaked Stealth Elite, and an Elite wielding both a Plasma Rifle and Needler at the end.
- "Cairo Station" also has an unusual case of a Unique Ally. In the first hangar, you encounter the "Bloody Marine", a Marine that wears less armor than usual and is covered in blood. Despite his unique model, he is of absolutely no relevance, has no unique behavior, and no other Marine appears in that state anywhere else.
- As part of the journey to unlock the "IWHBYD" skull, you face off against seven waves of Elite Ultras, some of whom are using Battle Rifles and SM Gs. These are the only enemy Elites in the game who use human weapons.
- In "Outskirts", you encounter a convoy of Shadows. Despite receiving an entry in the game manual, it is undrivable, only found in this level, and overall acts more as a set piece than an enemy.
- In "Delta Halo", some Jackals carrying Plasma Rifles are encountered at the second structure.
- At the end of the underwater passage on "Regret", you encounter a group of stealth-cloaked Grunts, which are never seen again (as enemies).
- The Marines in "Sacred Icon", who are indirectly encountered. You can still fight them from across the pit (and grenade-jump across). A trigger kills them if you go around the corner.
- "Sacred Icon" contains the only two friendly Jackals in the series. They'll probably die when the Flood first appears, and won't follow you to the next half of the level even if they do survive.
- "Quarantine Zone" has a single Sentinel that shoots with Needler rounds instead of the Sentinel Beam. According to one of the programmers, it was a rejected concept they forgot to remove.
- "Quarantine Zone" is the only level in the series where you encounter Flood-controlled vehicles, thus also making it the only level where you face off against Scorpions and Warthogs. Among their vehicle selection, there is just one Gauss Warthog.
- "Gravemind" had the "Honor Guard Councilor", a one-off enemy type who appears at the end of the Mausoleum battle. It is actually a glitched Zealot Elite,note and this is the only Zealot fought on difficulties lower than Legendary.
- "Gravemind" is also home to the only enemy Spec-Ops Grunts and Elites in the game (they otherwise only appear as the Arbiter's allies during some of his levels). Likewise, an Elite during the Mausoleum battle can be seen using a Fuel Rod Gun. "Gravemind" also features a single Hunter fighting Covenant Loyalists in one of the gardens; like the "Keyes" example, this is the only Hunter in Halo 2 that is not paired up with another one.
- In "High Charity", in the Prophet's inner sanctum, some cloaked Flood will spawn on higher difficulties. In addition, a single Flood Combat Form carries a Brute Shot, while a few others carry Brute Plasma Rifles.
- During "The Great Journey", Brutes operating vehicles unusually carry the regular Plasma Rifle rather than the Brute Plasma Rifle.
- Halo 3:
- At the first evacuation point in "Sierra 117", there is a Grunt using a Heavy Machine Gun Turret to fire on a Pelican. This is the only Grunt in the game that uses this weapon.
- In "Tsavo Highway", on higher difficulties, some sniper towers contain Brutes with Beam Rifles.
- In "Floodgate", going through the ridiculous steps of knocking the dead Elite Ultras in the ship down a level, then busting open blisters and allowing the Infection Forms to animate the Elite corpses will give you Elite Ultra Combat Forms, the only place this is possible in the game.
- In "The Ark", the Grunt Heavy manning the Phantom's door gun in the Scarab arena carries a Brute Spiker instead of the usual Plasma Pistol.
- During the flight section in "The Covenant", a Phantom is among the enemies you encounter. Unlike every other Phantom in the game, which follow a scripted path, this Phantom will actively pursue the player.
- At the beginning of "Halo", a Flood Brute Combat Form carrying a Gravity Hammer is dropped by a dispersal pod. A Flood Marine Combat Form armed with a Rocket Launcher appears during the standoff outside the Control Room. Going through the last tunnel of the Warthog Run, some Flood Elite Combat Forms appear on one of the raised platforms with Fuel Rod Guns. These are the only times Combat Forms spawn with these weapons.
- "Halo" is also the only mission where the Auto-Turret can act as an enemy, and even then only if you had the foresight to deploy one before 343 Guilty Spark's betrayal.
- Halo 3: ODST:
- On lower difficulties, on "Tayari Plaza" your first encounter with the game's Hunters will feature a pair of one blue Hunter and one gold-plated "Flak" Hunter. This is the only time in the game where the two types of Hunters are mixed together.
- "Kikowani Station" has the game's only enemy Scarab; you fought four of them in Halo 3 for comparison.
- "Data Hive" has two. The NMPD Officer, after collecting 29 audio logs, will turn on the Rookie because He Knows Too Much if you follow him into the argon-filled room with Daniel Endesha's corpse. This is the only time in the entire series that you have to fight a human enemy. "Data Hive" is also home to the Drone Captain Leader, which is a stronger Drone with energy shields. This enemy is more common in Firefight, but this is its sole appearance in the campaign.
- Halo: Reach:
- In every level of this prequel, there is a special hidden Elite who will randomly appear out of nowhere in certain areas if you're fast enough in playing the level. These Elites, nicknamed "BOBs", give you a load of points when killed (to add to your credits if scoring is turned on) and a special medal if your Xbox Live account is linked to Bungie's site, but if you don't kill them fast enough they will disappear. BOBs come in two flavors: Gold Spec-Ops Rangers and completely white, random model Elites, similar to the aforementioned Honor Guard Councillor. The second variety's white coloration is due to a spawning error where the game "forgets" to add the correct color to the Elite character model.
- Similar to the BOBs, the first level contains a lone Stealth Elite (different color than the cloaked Spec-Ops Elites encountered later) nicknamed "Bill", which can be spotted just before the moas first appear. If killed, he drops a datapad that can be read. This also may be a leftover from a Dummied Out objective.
- In "ONI: Sword Base", one room contains a group of Grunts carrying Plasma Rifles.
- There's one point in "Nightfall" where you fight a pair of King Kong-sized lizard-gorillas (referred to as Gúta
), who are basically part of Reach's local wildlife. They're tougher than Covenant, but not so tough that you could call them a boss battle or anything. They're never seen or heard of again afterwards, making the whole encounter something of a Big-Lipped Alligator Moment. - "Long Night of Solace" is the only level that features Space Banshees, Phantom Gunboats, and Seraphs. This is in fact the only mission in the series where you encounter them (a side effect of being one of the only missions actually set in space).
- During the Mongoose run in "The Pillar of Autumn", a pair of Scarabs drop down to intercept the player. This is their only gameplay appearance in Reach. Functionally, they are essentially the Halo 3 Scarabs without the ability to damage or destroy them. Digging around the game's audio files reveals that a proper Scarab fight was planned for "Tip of the Spear", but cut.
- In "The Pillar Of Autumn", a Jackal with a Plasma Rifle is in the room after the shipyards.
- The Elite Field Marshal is the only one of its rank in "Pillar of Autumn". It is basically a high-ranking Zealot that rapidly fires a Fuel Rod Gun and throws grenades at the player. When its shields are down and when the player is close, it unsheaths its Energy Sword in an attempt to One-Hit Kill the player.
- In Halo Wars, the eighth mission Anders' Signal has Brutes (as well as Choppers), the only time in the campaign where they appear as enemy units. They are fought at the beginning, and their appearance is completely overshadowed by the subsequent introduction of the Flood.
- Halo 4:
- In "Midnight", Forerunner artillery turrets are encountered throughout the Broadsword segment.
- Also, in "Midnight", there is a single Sentinel that can become an enemy as a requirement for the "three battle rifles" easter egg. This is the only instance of an enemy Sentinel in Halo 4.
- In the Spartan Ops "Switchback" mission, there is a Promethean Crawler that uses a Lightrifle. This particular Crawler is referred to as the "Lightrifle Crawler" on Halopedia and Halo Nation and is most likely an occurrence of a Glitch Entity.
- In Halo Wars 2, "The Foundry" features the only enemy Banished Honor Guard, who is encountered before capturing the Scarab.
