Secondary attack only in round

[ckdragons]

The creature with both a bite and 4 tentacle attacks. If that creature wanted to attack the tentacle by itself as a single attack action, would it gets plus +1/2 Str damage or full Str damage? And it would be at Full BAB or at the -5 BAB?

[Name Violation]

-5, 1/2 str

Most creatures possess one or more natural attacks (attacks made without a weapon). These attacks fall into one of two categories, primary and secondary attacks. Primary attacks are made using the creature’s full base attack bonus and add the creature’s full Strength bonus on damage rolls. Secondary attacks are made using the creature’s base attack bonus –5 and add only 1/2 the creature’s Strength bonus on damage rolls. If a creature has only one natural attack, it is always made using the creature’s full base attack bonus and adds 1-1/2 times the creature’s Strength bonus on damage rolls. This increase does not apply if the creature has multiple attacks but only takes one. If a creature has only one type of attack, but has multiple attacks per round, that attack is treated as a primary attack, regardless of its type. You do not receive additional natural attacks for a high base attack bonus. Instead, you receive additional attack rolls for multiple limb and body parts capable of making the attack (as noted by the race or ability that grants the attacks).

Hoof, Tentacle, Wing Secondary
link

[Derklord]

Short version: As long as the creature has two or more different types of natural weapons, secondary attacks stay secondary, period.