Bombs are cylindrical projectiles used for attacking certain bosses as well as enemies. Bombs come in three different colors, each color represents each type. If one holds it, it can self-destruct if held for too long; it will signal a slightly small tingle if held for too long.
The orange one is called Flare Bomb; when thrown, it can explode into a small flame and deal heavy damage depending on whom it is thrown at. Flare Bombs appear in Deathmatch and Co-Op as well as certain bosses in game like Cocoon and Arena Muruk.
The green one is called Daze Bomb; when thrown, it can explode on an enemy to inflict a Daze status. If thrown on the ground, it can be activated if walked or jumped upon. If one throws a Daze Bomb on the ground and no being touches it for awhile, it will deactivate itself and return to safe mode (the state it was before you picked it up). These bombs appear in both mode of Multiplayer as well as certain bosses in-game such as Marbas.
Finally, the white one is called Heal Bomb; when thrown to a designated area, a heal circle would appear there. Similar to regualr Recovery Circles and Magic Circles, they can be diffused and stay for a long while. In-game, these bombs are usually everywhere if Calista and Mirania are not present such as the Arena. In Co-Op, there is at least one in each stage. In Deathmatch, only certain stages have heal bombs; stages like Arena and Mysterious Forest.