Bob-omb

Bob-ombs are NPCs that appear in SM64 and SM64DS, they are small cartoon-bomb shaped beings with yellow shoes, white eyes, and a grey top. They appear in either Black or Pink in the base game, however Personalization can cause more colors to appear.

Black Bob-omb
When spotting Mario, they will run up to him and follow him around before exploding. Mario can pick up the Bob-omb, either exploding in his hands if left held too long or can be thrown to detonate it.

Pink Bob-omb (Bob-omb Buddy)
Friendly NPCs that are stationary and may talk to Mario when interacted with. If you have defeated the Big Bob-Omb, they may open a Cannon for the player to use. They appear in most of the courses (except Big Boo's Haunt, Hazy Maze Cave, Lethal Lava Land, Dire, Dire Docks and Tick Tock Clock) to open the cannons on their respective courses. You can talk with them, but they won't open any cannons until you defeated Big Bob-omb, if you defeated him, they'll be able to open the locked cannons that appear in their respective courses.

Bom-omb
It's unclear why, but some players remember Bob-ombs as a Bom-omb. It might be a case of the Personalization A.I. changing the dialogues or signs in the game, or it might just be misremembering.

Hats
In some reports, Bob-Omb Buddies are the same color as the rest of the Bob-Ombs. They can be told apart by the hats they wear over their fuses. The hats resemble patrol caps worn by military personnel and are colored pink.

Disarming
In some personalized copies, if the player picks up and immediately puts down a Bob-omb, it will be "disarmed." It will then be unable to explode, and instead randomly wander about aimlessly. When a Bob-omb is disarmed for the first time, there is usually a dialogue box explaining the mechanic. However, this anomaly is also rather buggy or incomplete, as several have reported disarmed Bob-ombs still explode upon being thrown or chase the player only to never explode, just being minor nuisances.

Storyline Alterations by Enemy Discoloring
Occasionally, discolored Bob-Ombs will be incorporated into an "alternate storyline", usually for Bob-omb Battlefield. While reports are inconsistent, they tend to explain that a third neutral faction enters the Bob-Omb war (usually in a distinct color like Blue) and will attack both Mario and black Bob-Ombs. Dialogue, and in rarer cases entire Missions and courses may be changed to accommodate this.

So far, all confirmed reports include only one "anomalous" Bob-omb faction, which has the colloquial name "Bob-omb Insurgents" due to several copies with this phenomenon referring to the party as a "Group of chaos-wreaking Bom-ombs trying to end the war by any means necessary!". Besides this, there is little consistent data on the colors and unique behaviors of Alternate Factions.

Bob-omb Buddy Headwear
In some reports, Bob-ombs or Bob-omb Buddies (occasionally both) will have unique hats that distinguish them from eachother. These are usually colored Pink and Black respectively, however may be different. They usually share the same model as Mario's Hat and may even be Wing Caps that the player can pick up and wear if the Bob-omb is defeated.