Diablo III- Skills Article XCVIII: The Witch Doctor, Primary Skills- Firebomb

Firebomb (10 Mana): Hurl a flaming skull at the target or targeted area that explodes for 85% weapon damage as Fire damage to all enemies in an 8-yard radius.

Firebomb is the primary skill that sits in competition with Corpse Spiders as the Witch Doctor’s other option for basic multiple-enemy damage.  While the typing is sad and the damage isn’t amazing, the area of effect is pretty good and can make it relatively easy for you to take out clusters of enemies.  Unlike Corpse Spiders, which is pretty much equally effective no matter how many allies you have, Firebomb benefits hugely from melee allies who can pull enemies towards them or manipulative allies like a trap-laying Demon Hunter, as either one of those will cluster enemies into smaller areas where you can more destructively explode them.

Flash Fire (10 Mana): Hurl a flaming skull at the target that deals 85% weapon damage as Fire damage and may bounce to up to 6 subsequent enemies, dealing 15% less damage each time.

Flash Fire relies less on enemies grouping up in a single small area, and more on enemies being near other enemies.  Like the Demon Hunter’s Hungering Arrow, while you can’t directly control it, that doesn’t make it noticeably less useful for handling clusters or spreads of enemies.  The damage remains a bit low, though, and the reduced damage on each subsequent hit means this isn’t going to be a very useful skill for dealing with small numbers of high-power enemies.

Roll the Bones (10 Mana): Hurl a flaming skull at the target or targeted area that explodes for 85% weapon damage as Fire damage to all enemies in an 8-yard radius.  The skull continues in that direction, bouncing (and exploding) two additional times.

Best used against a stream or column of enemies headed towards you, Roll the Bones makes Firebomb a much nastier weapon when there are large or slightly spread out clusters of enemies.  Still not stellar against smaller numbers of more powerful enemies, but a fair sight better than Flash Fire in some respects- particularly when you’re trying to make sure you hit the ranged attackers in the back ranks of an attacking enemy group.

Fire Pit (10 Mana): Hurl a flaming skull at the target or targeted area that explodes for 85% weapon damage as Fire damage to all enemies in an 8-yard radius and setting that area on fire, dealing 8% weapon damage as Fire damage per second to all enemies in the area for 3 seconds.

Fire Pit is a very useful form of Firebomb if you are dealing with either slow-moving enemies or a mass of enemies advancing in a particular direction.  While the damage isn’t terribly great, it is highly spammable with its modest cost, and the lingering damage areas stack fairly well.  As with the other forms of Firebomb, very nice if you have some ally (or perhaps a summon) doing something to keep all your enemies corralled in a small area.

Pyrogeist (10 Mana): Create a towering flame at the target location that lasts for 3 seconds.  This flame attacks the nearest enemy with a constant stream of fire that deals 47% weapon damage per second to that target.  You may only have one such flame at a time.

Pyrogeist is much less effective at dealing a raw large heap of damage out than other forms of Firebomb, and the lack of an area-effect makes it much less useful in multiple-target situations.  However, the damage it can deal to a single target, focused, is notably higher than the other forms of Firebomb, and since it has a good range (from the original fire column) on its attack and actually targets an enemy, the damage is much more reliable.  Sadly, you cannot have multiple Pyrogeists, so this is more of an anti-boss form of Firebomb, for situations where you’re running your Mana out regularly through other means.

Ghost Bomb (10 Mana): Hurl a flaming skull at the target or targeted area that explodes for 85% weapon damage as Fire damage to all enemies in an 8-yard radius and 20% weapon damage as Fire damage to all enemies in a 28-yard radius.

For situations with especially large or spread out enemy forces, particularly forces that include imps and other small enemies, Ghost Bomb will make sure that you manage to hurt most of what there is to hurt.  The damage isn’t terribly impressive on the larger area of effect, but throwing out a barrage of Ghost Bombs will rack up a lot of total damage in a short period of time if there are even three or four things to hit in the area.  If you’re playing in a party and nobody is clustering or controlling the demons very well, this can be useful.