M274 Ultra-Light All-Terrain Vehicle

M274 Mongoose "...the most Buddhist land-based motive system in the UNSC’s arsenal..."

- UNSC Marine The Mongoose, officially known as the M274 Ultra-Light All-Terrain Vehicle, is a United Nations Space Command ground reconnaissance vehicle. It holds two people, a driver and a passenger.

Overview
One of the fastest ground vehicles available to UNSC Marine Personnel is the M274 Ultra-Light All-Terrain Vehicle, also known as the Mongoose. Essentially four wheels and an engine, this ATV can travel rapidly over nearly every type of terrain. It can be viewed as the smaller cousin of the Warthog.

It can be seen as an analog to the Ghost but unlike the Covenant vehicle, it has no armament itself. The Mongoose possesses no defensive or offensive capabilities what so ever. As a result, troops often seat weapon specialists behind the driver to provide much needed fire support during combat. What it lacks in firepower however, it makes up for with raw speed.

This vehicle is reportedly unwieldy and difficult to control at high speed, thus making the passenger's role of vehicle defense all the more difficult. Both driver and passenger are completely exposed to the elements and enemy fire. As a result, they are extremely vulnerable. An ATV slowing down in a combat zone is tantamount to suicide. The Mongoose survives most encounters through sheer speed, ensuring it is in and out of an enemy position before heavy firepower can be brought to bear on it.

It can be used as a last resort offensive vehicle when the passenger is equipped with heavy armament and is useful for chasing down fleeing enemies or ambush.

The UNSC Elephant Vehicle apparently has a vehicle bay that fits one Mongoose, perhaps to use as a courier during communications black out, a personnel transport in friendly terrain, an advance scout or a last resort escape vehicle.

Operation
Lacking any in-built weaponry of any kind, drivers are advised to ensure a fast speed at all times during combat. The addition of an armed passenger is recommended, but due to the high speeds and the handling problems of the Mongoose, general suppressive fire is all that can be expected.

The Mongoose is more than capable of outrunning the Covenant Ghost, but attempts to combat one in the ATV are ill-advised. The Mongoose is best suited to rapid reconnaissance missions and quick relocation of UNSC sniper teams.

The Mongoose is impossible to hijack, which is a vital advantage while trying to "splatter" enemies. Although if there is no one occupying the passenger seat, you could get in an enemy's Mongoose while he's driving and possibly shoot the ground in front of him or shoot him when he gets out.

Halo 3 Campaign
In the Halo 3 campaign they seem to be vitally important on some levels, for quick transportation through cramped and wide open areas but most especially on The Storm where the first objective is to chase down a Scarab with a dozen marines mounted on Mongoose ATVs. There is another level that has you use the Mongoose for transport through a UNSC base, which shows how often you might use it throughout Campaign.

Halo 3 Multiplayer
Due to the high-speed nature of the Mongoose, it is a very good vehicle for objective based games, such as CTF and Assault. Although passengers are very exposed to enemy fire, the ATV is often moving too fast to hit without a lucky shot or a weapon that can lock on to the Mongoose.

It is not designed for aggressive strikes against an enemy, but rather for a quick recon run, flag snatch or bomb drop. Head-on attacks place the driver and passenger in great danger. If combined with a passenger wielding an M41, the Mongoose becomes a potent Wraith hunter, its high speed and maneuverability allowing it to run rings around the more cumbersome tank. When the passenger is using the MA5C ICWS Assault Rifle the Mongoose can be used for drive-by attacks on enemies by driving around them, and for suppressive fire.

If either the passenger or the driver have a Sniper rifle in their possession, then it can become a useful sniper team relocation vehicle.

Involvement in Halo 2
This vehicle was intended to be put into Halo 2. However, it was left on the cutting room floor and Halo 2 launched without it, because this prototype version did not behave as well as Bungie wished. They tried putting dual coaxial machine guns or something similar on the front, as well as making the biped hold a weapon while operating the ATV. In the end, it wasn't balanced and didn't fit into the gameplay well, so they took it out. It will appear in Halo 3 as a vehicle for both the single-player campaign and multiplayer. Bungie finally figured out how to balance it by making you use two players for an effective offense; for you wont stand a chance without a passenger, unless you move fast.

Like the Warthog, Pelican and the Scorpion, the Halo 2 Mongoose resembles the animal it's named after. Notice in the image to the left the "ears" jutting out on each side of the front and the "eyes" in the windshield. It also resembles a mongoose by its agility, speed, and size. The Halo 3 official Mongoose resembles the small mammal as well, but not as much.

Several modders have managed to insert the Mongoose into Halo 2.
 * Modded for Halo 2

There have been several Halo CE maps with models based off the Halo 2 mongoose, such as Yoyorast Island.
 * Recreated in Halo CE

Halo 3 Beta

 * The Mongoose was one of the few vehicles to appear in the beta. Some players reported that it was very hard to "splatter" enemies, due to a shorter width than most other vehicles.
 * As seen in beta, the Mongoose is able to use the Man Cannon to propel itself into the air by just driving over one. This is very helpful, for it is quicker to get to the enemy base on Valhalla using this method, rather than any other on the Mongoose.