BOB

The BOB is a special type of enemy encountered in Halo: Reach. The BOBs usually take the form of yellow/gold-armored Sangheili Rangers. In the ONI: Sword Base level, BOBs take the form of a white-armored Elite with randomly generated armor, ranging from Minor to Field Marshall. These white-armored BOBs always dual-wield Plasma Rifles, regardless of rank. The yellow/gold-armored Ranger class BOBs, on the other hand, have been seen with Plasma Rifles, Plasma Repeaters, Concussion Rifles, Fuel Rod Guns, and even Energy Swords.

Description
Killing one of the BOB's will reward the player the "Seek and Destroy" medal. However, the medal can only be viewed on Bungie.net. In the post-game carnage report, the BOB is referred to as a "Elite light vehicle". On Bungie.net, their description is simply "Wipe them out."

The name "BOB" is a reference to Bungie's Marathon video game series. All human characters in the series, besides the player, are known as "BOBs". "BOB" is an acronym for "Born on Board", a reference to the characters having lived their entire lives onboard the titular colony ship.

BOBs are considered Easter Eggs, and thus have no canonical explanation in the storyline.

Appearances
Weapon: Plasma repeater. Concussion rifle (on Legendary)
 * Winter Contingency:

Rally Point A: While looking for 3 Charlie, the player will find 3 different buildings, the first building is the one where you cannot find 3 Charlie, it has 3 spawn point for the BOB, one for every small section of the place. The second building is located next to the river, it has 2 spawn points, one inside a basement with a broken wall and another next to the death marines inside the building. The third building is located near the broken bridge, it has 2 spawn points, one on the dark building, next to the window, the other one is next to the death civilians. Weapon: Dual-wielding Plasma rifle
 * ONI: Sword Base:

Rally Point B: Just before fighting the hunters inside the base, a random armored Silver Elite can be seen on the courtyard. Inside the base, on the fourth floor, a radium armored Silver Elite can be found. These 2 BOBs will never despawn. Weapon: Plasma rifle
 * Nightfall:

Mission start: A golden Elite ranger can be seen on the broken bridge where the dead militia is. Rally Point A: One can be found on top of the smallest building on the settlement. Rally Point B: One spawns next to dead militia soldiers on the bridge. After it spawns it will go to a rooftop and will stay there. Weapon: Concussion rifle (first one). Fuel Rod Gun (Last 3)
 * Tip of the Spear:

Mission start: When heading to the first AA Cannon One can be found on the hill at the far left of the gun. Rally Point B: 3 can be found here, one in front the crash site in the rocks. The second one on a cave at the far left of the crash site. The third at the place where Bravo Generator is located on Invasion. Weapon: Plasma rifle
 * Long Night of Solace:

Mission start: a pod with a BOB inside can land on 3 random places. The first one is in front of the facility, over the small hill, the second one in almost the same place, but it will land near the human barriers, and the third one will land next to the platform where the Wraith can be found. Rally Point B: One can be found on the main controls of the corvette on the bridge. Another one can be found when you come back to defend the Pelican at the hanger, on the top floor. Weapon: Banshee
 * Exodus:

Rally Point A: When heading to the extraction point, a Banshee BOB will spawn near the docks and fly over the highest bridge. Rally Point B: Just when the chapter starts, a Banshee BOB will spawn at the far right of the tower and will fly over the extraction point. Another Banshee BOB can be found while clearing the beach at the end of the mission if the player is near the bridge. Weapon: Banshee
 * New Alexandria:

Mission start: If the first objective is not Club Errera, at exactly 5 minutes into the game a BOB Banshee can spawn on 5 random locations: 1. Nomolos tower, heading to the sea. 2. Nomolos tower heading to the glassed area. 3. From the glassed area to Club Errera. 4. Near the Hospital heading to the sea. 5. Near the Hospital heading to the glassed area. Weapon: Concussion rifle (First 3). Banshee (last one)
 * The Package:

Rally Point A: One can be found on the courtyard. Additionally, another one can be found inside the base, next to the Datapad. Rally Point B: On the final wave, if any Banshee was still flying, A phantom will drop one near the cliff. If the player destroyed all Banshees, a Banshee BOB will spawn just before the wave on the ice roof. Weapon: Concussion rifle.
 * The Pillar of Autumn:

Rally Point A: One will spawn at the far right of the zone where a large battle is being fought, under the UNSC Commonwealth, is almost impossible to sprint where it is without getting it to despawn. Another one will spawn in the garage on the next zone, exactly where the Scorpion spawns in Invasion. Weapon: Energy Sword
 * Lone Wolf:

If the player manages to survive until the generals start spawning, a BOB will spawn on the open area at the left of the mission start.

Trivia

 * Each BOB has a set time limit before it vanishes. For some BOBs, this time frame begins as soon as it is alerted to the player's presence. For others, the countdown begins once the player enters a certain area, thus it is possible for the player to miss the BOB entirely if it is not spotted.
 * On page 384 of the Halo: Reach Official Strategy Guide, there is a list of enemy point values. In this list, there is an enemy called a "Daily Challenge Elite", which has the same point value of a BOB (200 on Normal difficulty).
 * BOB's energy shields have the same strength of an Elite General.
 * There is a Daily Challenge called "Whats up Bob?" awarded for killing a Golden Ranger Class Elite.
 * Banshee BOB have no pilot, and do not award a Seek and Destroy medal, but they are Considered BOBs for the daily challenge "Golden Tree City"
 * There are 7 spawn points for BOBs on Winter Contingency, a possible reference to Bungie´s favourite number.