So, I made myself a mutagen warrior and just got the tentacle discovery at level 7, mostly for the roleplaying fun of it. Nevertheless, the rules text was a little vague, and so I decided to look up errata and discussion. I am now very confused.
To whit:
1) Am I correct when I believe that this "special" tentacle cannot be used in conjunction with weapon attacks at all, but that I can full attack with just the tentacle if I wish?
2) If yes, when i attack with the tentacle, is it secondary or primary with regards to attack/damage bonus and power attack? It is, after all, my only natural attack, even though it is a tentacle. Rules as written seem to indicate primary with 1.5x str to damage, overriding the table for "common natural attacks".
As a gm I would probably not allow a measly arm-length tentacle to rival a two-handed weapon in damage output. However, making the attack secondary seems rather harsh when it has to stand alone. Personally, I would say primary attack with normal damage for a one-handed weapon. Thoughts?
Actual post (not duplicate)
The tentacle from this discovery can be pretty tricky, and I don't know if I am 100% correct, but I will share my interpretation of it.
The reading for it says
Benefit: The alchemist gains a prehensile, arm-length tentacle on his body. The tentacle is fully under his control and cannot be concealed except with magic or bulky clothing. The tentacle does not give the alchemist any extra attacks or actions per round, though he can use it to make a tentacle attack (1d4 damage for a Medium alchemist, 1d3 damage for a Small one) with the grab ability.
The part that can be confusing is where it says it does not give you any extra attacks per round. That can be interpreted a few different ways. How many attacks do you have? Some GMs will look at a level 7 fighter (BAB 7) and say you have 2 attacks, so you can attack with the tentacle and your weapon as long as you don't increase your total number of attacks (2).
Well what if you are two-weapon fighting and you have improved two-weapon fighting? Now you have 4 attacks as a level 7 fighter (BaB 7). Some GMs will allow you to substitute the tentacle in for off-hand attacks as long as you do not attack more than 4 times total in a round. I think that is fair, but the rules aren't very clear so it's probably best to run it all past your GM.
Your second point is easier. The rules are clear that if it is your only natural attack you get to use it with 1.5 STR modifier at full base attack bonus, but you only get 1 attack with it when you do that, no matter what your BAB is you won't get iteratives on the natural attacks. If you attack with it while attacking with manufactured or additional natural attacks (if you ever gain them) it would be treated as a secondary weapon.
1) Am I correct when I believe that this "special" tentacle cannot be used in conjunction with weapon attacks at all, but that I can full attack with just the tentacle if I wish?
You can't get MORE attacks because of the tentacle but you can use it to gain the same amount. So the average PC can always make 2 unarmed attack plus extra's from BAB. So your character could make a weapon attack [full bab] and a tentacle attack [-5bab] plus the normal secondary bab attacks: both are making the same number of attacks. So if you are a 6 bab you could make weapon attacks of full and -5 and a tentacle of -5.
2) If yes, when i attack with the tentacle, is it secondary or primary with regards to attack/damage bonus and power attack? It is, after all, my only natural attack, even though it is a tentacle. Rules as written seem to indicate primary with 1.5x str to damage, overriding the table for "common natural attacks".
Tentacles default to secondary. It's listed in the bestiary under natural attacks. However, "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 the creature's Strength bonus on damage rolls." So if the only natural attack he has is that tentacle, he's in luck.
Thank you both for weighing in on this. I would tend toward the interpretation that this particular natural attack must stand alone, or perhaps be a useful attack of opportunity. This also makes the added damage more reasonable - at least until I add a anacondas coils belt to the mix :-)
While two weapon fighting in this way is an intriguing option, the char is a brutal two-hander, so I will avoid that bag of worms.
Cheers!