Alchemist's Bombs and Vital Strike: What is "bonus damage?"

Question

According to the PRD:

Bomb: On a direct hit, an alchemist's bomb inflicts 1d6 points of fire damage + additional damage equal to the alchemist's Intelligence modifier. The damage of an alchemist's bomb increases by 1d6 points at every odd-numbered alchemist level (this bonus damage is not multiplied on a critical hit or by using feats such as Vital Strike). (Emphasis: Bold)

What exactly is the bonus damage the parenthetical text is referring to?

• The Intelligence Modifier added to the bomb?
• The Increase in Damage by die/level?
• The Splash Damage dealt?

Answer 1

The bomb is a weapon for nearly all feats and abilities that affect weapons, according to the Alchemist class rules.

The alchemist bomb's damage is:

• 1d6 base damage
• Int bonus (bonus damage)
• 1d6 bonus from alchemist levels (gained at even levels and also bonus damage)
• 1d6+INT+(1d6/2 alchemist level)

Vital Strike increases only the first 1d6 damage (the base damage). Similarly, if you confirm a Critical Hit, you will double only the base damage.

So if anything increases the weapon's damage, treat the first 1d6 damage as the weapon damage, everything else is bonus damage, or precision damage, or fire/cold/eletricity damage, etc.

Answer 2

The bonus damage are the dice added every odd Alchemist level.

The bomb has base weapon damage, the 1d6, adding Int to the roll as additional damage. Class level adds bonus dice, much like sneak-attack dice, or the extra dice of damage from a flaming weapon, which Vital Strike already calls out as not being included in the extra attack. These dice are the ones considered 'extra', and as per the Multiplying Damage section are not multiplied, just the base damage. In a Vital Strike, the damage from Int would also not be repeated, as Vital Strike's list is open-ended, saying "...and other damage bonuses." The Int bonus is slightly unclear in the context of a Critical Hit; it could be a 'modifier' to the damage, or considered as separate.