I was looking through the Monster Burner at some of the spiders, and I was wondering what stat or skill they use to bite. The section on spiders suggests that they first lock and wrap, then they bite, and then they wait for their opponent to become sick and incapacitated. I know that they use either Agility or Power to lock, but what do they use to bite? Some of the spiders in the list section have the Brawling skill, and some lifepaths have Brawling as a skill, but not many do. What do the spiders that don’t have Brawling roll on to see if they hit? Savage Attack seems like another viable choice, but none of the spiders have that, and it isn’t a spider lifepath skill anywhere.
Brawling is for, you know, fighting someone who isn’t already incapacitated. The attack profile you described would involve Agility or Power to lock, then incapacitating your opponent, then you saying “So he’s all wrapped up, I can just bite him, right?” and the GM saying “Yes you can.”
It’s like there isn’t really a skill for smothering someone with a pillow while they’re sedated.
I see your point about it not being needed in most cases. However, there are situations where you need to know how quickly the spider poisons its prey. For example, four spiders are facing four adventurers. One adventurer is clad in plate mail and gets wrapped up by his opponent. The other three adventurers slay they spiders in the next few actions. Is the guy in plate mail poisoned? If so, then how many times was he bitten?
This is just an example. I’m sure you can come up with others where it’s useful to know the dice mechanics for figuring out if a spider successfully bites.
Would spiders with the brawling skill use brawling? Would spiders without it use beginner’s luck brawling?
Generally if you need to fight someone but don’t have a fighting skill, it’s Beginner’s Luck.
Yes, the spiders without it would use Beginners Luck Brawling. Unless they were learning a more complex Spider Martial Art, in which case it would be BL Boxing 
The suggestion I get from the LPs is that not all spiders are actually much good at biting anyone who can resist at all. Biting someone who’s entirely wrapped up is Say Yes territory. But biting someone in armor? Might be time to roll your Beginner’s Luck. Now you’re learning how to use your fangs as weapons, not just as tools. Or you could say that all armor has holes, and trying to bite through it isn’t actually all that hard. One bite per action the Spider spends biting.
Yeah, I’d agree with you, Wayfarer. Not all spiders will be “warriors”. Generally they rely on stealth and ambush, not fair fights. If you hunt by poisoning things that blunder into your web and waiting from them to succumb, what do you really need Brawling for?
The venom traits (p. 154, et seq., MonBu) describe how long it takes for venoms to act.
A spider’s lock is very powerful indeed: remember that all spiders wrap from instinct, and it’s an Ob8 Power test to break the lock, or have someone burn or cut the wrapping off. From then on, the locked victim can only position with Let 'em Come, so a spider that wins its lock takes the advantage at Hands, and keeps it. That allows the spider to rock in and out, wrapping a bit more, chancing a bite (the victim’s armor may fail, or be abraded, and the spider might have Piercing Fangs) until the victim is completely wrapped.
Spiders must achieve a Mark to inject venom, so I think it’s fair to require a successful Brawling test* (skilled or not… all the in-your-face fighter spiders have Brawling**) that gets through armor to attempt to inject their venom. Of course, with a completely incapacitated victim, the spider can spend two actions removing the victim’s helm and then it’s a straight shot for a bite in the eye. Fangs have a weapon speed of 1 (per the example spider in BWG), which tells you how many doses are going to be delivered, if each one gets a Mark; Add is not listed, but I’d give them the same as a bare fist: 2. i.e. The example BWG spider would need 3s on its B5 Brawling to inject its venom into a victim.
If I were playing the BWG spider against armored opponents, I would be looking to get locks on everyone engaged with me, as soon as possible, then just keep wrapping them up, biting as soon as it was viable to do so. Naturally, I’d want to capitalise on the spider’s cunning, and look to pair up {Avoid, Lock} actions in volleys, and otherwise escape incoming damage.
*In your example, because time is at a premium here: there are 3 adventurers looking to Engage at the top of the next exchange. If a player spider had fully wrapped a solo NPC victim, I would say yes to deliquescing insides and a hearty meal. If all four player adventurers were fully wrapped, it would be time to ask if they each want to spend a Persona point for some complications, or rack up four hearty meals and a TPK.
**Implicitly, if you don’t have Brawling in your arachnid lifepaths, you’re not an in-your-face fighter. Yet.
Thanks, that was a very helpful way of looking at it!
I was thinking of burning a Good Guy Spider to replace my current William Munny character. Now I just have to decide if he’s the kind who bites people or not.
Yep, I think that’s the way I’m going to look at it.
Thanks homie. That’s exactly what I was thinking but completely failed to actually say.