Bombs are an enemy and summon that has appeared in most main Final Fantasy titles (Except the first) and a majority of the spin-off titles. Bombs usually appear as bright orange, floating fireballs with arms, eyes and a strange, twisted mouth. Bombs are named such as they have the famous ability to self-destruct, often after receiving three or more hits from the player or once they are hit with an element they are immune to (usually fire).
Several variations of the Bomb include Balloons and Grenades. More powerful versions of the bomb that have more devastating self-destruct attacks as well as having a different appearance, which is simply a color swap to a dark blue or gray. In Final Fantasy IV, there is a boss version known as Mom Bomb, which initially appears as a normal Bomb before transforming into a frightening flaming cloud. While most bombs have the fire element, some variations are not.
As a Summon
Bombs make appearances as summons in a number of titles, and much like the enemy variation, has the tendency to self-destruct on its opponents as an attack.