Cut Halo 2 enemies

During the development of Halo 2, a number of creature designs were considered for inclusion by Bungie to serve the role of enemies, ambient AI and other miscellaneous NPCs. Not all of these concepts made it to full 3D development.

Space jellyfish
The "space jellyfish" is a deleted species of ambient life which was to be featured in Halo 2. According to Dave Dunn, the space jellyfish was planned to appear in the campaign level The Arbiter (then known by the name ). It was conceptually based on hypothetical lifeforms which might exist in the atmospheres of gas giants such as Jupiter. Dunn was planning to have the space jellyfish make sounds which he described as "bloop bloop". However, another Bungie employee deemed the concept too preposterous, resulting in it being cut from the game. However, its model is still present in the Halo 2 games files under the filename "Space_Blimp".

Disintegrator Hunters
In the files for Halo 2 for Windows Vista can be found several audio samples under the pathway. The files; named  have three components; one for the weapon fire starting, one looping and one for the weapon fire ending. The names seem to reference the Disintegrator weapon cut from Halo 2, seeming to indicate that at some point in development a Hunter enemy variant equipped with the Disintegrator weapon was planned for inclusion in the game.

Sharquoi
Originally intended for inclusion in Halo: Combat Evolved, the Sharquoi are originally descended from the Drinniol - a species originally appearing in the Marathon franchise. The Sharquoi's concept art was featured in the Limited Collector's Edition behind the scenes documentary, while storyboards featuring them were later showcased. The storyboards in question showcase the Sharquoi as one of many species depicted on the Covenant murals intended to be used in the opening cutscene for Sacred Icon.

The Sharquoi were saved from being rendered non-canon thanks to the release of Conversations from the Universe, with the Sharquoi mentioned in passing in a conversation between two Elites. The 2017 novel Halo: Envoy later expanded on the Sharquoi and their in-universe mythos.

Flood juggernaut
The Juggernaut's model and AI are still present in the game files, allowing the NPC to be added to gameplay via modding, similar to the Huragok in Halo: Combat Evolved. The Juggernaut stands nearly twice as tall as a Spartan or an Elite. It has two large tentacles that can kill the player character with only one hit on Legendary difficulty. The player can survive this hit on lower difficulties, though will often be sent flying through the air. Finding cover is ill-advised, as the Juggernaut will hit it out of the way, sending the object a great distance and killing the player if it connects. They also can jump much higher and farther than regular combat forms can. They often jump high in the air at the player character when noticed, sometimes landing on top of them and killing them instantly. The Juggernaut will also sometimes forget the player character is there remain still for a few moments. The Juggernaut is highly resistant to damage. Powerful weapons such as the shotgun and rocket launcher are all but necessary against it. Standing under the Juggernaut and meleeing it will cause the enemy to recoil - doing this repeatedly can stun-lock the Juggernaut.

Through modding, it has been found that the Juggernauts have a defensive position; stopping and moving their whip-like appendages in front of their body in an X formation. When running low on health, some occurrences have happened where the Juggernaut goes berserk, waving its tentacles around wildly before striking the player with speed. As Bungie never created a death animation for the Juggernaut, when it has ran out of health, it simply freezes in place. The Juggernaut also has a taunt animation, in which it slams its tentacles on the floor and "roars" at the player.

Although the model, textures, etc. for the Juggernaut are stored in the files of the level "High Charity", there are no spawn points for it. Modders and Halo 2 for Windows Vista players can fight against the Juggernaut on the level by switching them to spawn in place of another character's existing spawn point. Code within the files for the levels The Oracle, Sacred Icon and Quarantine Zone indicates these missions were to have had Juggernaut spawns within them, though the level files themselves do not contain the Juggernaut assets. The Oracle would have one Juggernaut hidden in the fog (not able to be fought), and one attacking the Flood research laboratory later on in the mission. Another would spawn in the defense section near the end of Sacred Icon, while six were to spawn on Quarantine Zone - likely due to the abundance of heavy vehicles in the mission. These Juggernauts would have spawned as follows; two in the canyon in front of the destroyed Sentinel manufacturing facility, one inside, one outside the exit and two more at the entrance to the gondola. This would have lead to nine possible Juggernaut encounters in the game, with eight as actual combatants.

Interestingly, The Oracle retains some cut dialogue in the level files referencing the planned Juggernaut fight. The cut dialogue is spoken by Rtas 'Vadum, and serves to warn the player of the Juggernaut's entrance and a planned weak point of the creature - shooting it in the eye.

Juggernauts remain in the game files of Halo 2: Anniversary, as they were in the original Halo 2 game. In classic graphics, the Juggernauts display their texture, though in the remastered campaign graphics the models simply display without any kind of texture map. Killing the Juggernauts with Halo: The Master Chief Collection campaign scoring enabled does not award any points for killing the enemy, and in the post-game carnage report does not count the Juggernaut as its own enemy. Due to the need to spawn the Juggernaut in by replacing an existing enemy spawn, the Juggernaut kill is counted as the enemy that would have spawned in its place - for example, if the Juggernaut replaces a Flood combat form spawn, the postgame stats will count the Juggernaut kill as a combat form kill.

Shielded carrier form
As their name suggests, these enemies take the form of Flood carrier forms wielding the point defense gauntlets favoured by Jackal infantry. As such, these carrier forms are effectively shielded from the front. They otherwise perform in the same way as their unshielded counterparts.

The shielded carrier forms can be found still in the files of Halo 2, and like the Juggernauts can be spawned into levels through modding.

Needler Sentinel
"The needler sentinel that was cut from the game dropped a sentinel arm weapon (identical in appearance to the beam weapon) that shot small red needles. It even had its own unique sentinelly, needly crosshair and pickup image."

- David Candland speaks out about the Needler Sentinel.

While Halo 2 features many types of Sentinel, the game was originally going to feature more. The Needler Sentinel was one such enemy, intended to be equipped with a needle-firing variant of the Sentinel beam, which was cut from the game alongside the Sentinel.

Other cut Sentinel weapons include a Grenade Launcher and Charged Bolt, which may possibly indicate a few other cut Sentinel enemy types.

This cut enemy should not be confused with the similarly-named Needler Sentinel glitch that did make it into Halo 2, which is the result of an improper weapon assignment in the game's code rather than an intended enemy type.