Invested Item: Spider Box

This item was a thought experiment that led to some discussion about Target: Group, and items maintaining concentration. I know these have been discussed on the boards in the past, but I wanted to see if I am thinking correctly about this.

The box is roughly square, about a hand's length on each side, and a hand's width tall, with a hinged lid. The enchantment is designed to create a swarm of spiders that pour out of the box when the lid is opened. (A booby trap for prying eyes in one's sanctum, or a special gift for that special someone :imp: )

The item requires 6 pawns of vis to open (wood 2, small x3).

Version 1:
Effect: CrAn30 Create a swarm of spiders
Base 5, +1 Touch, +2 Sun, +2 Group

Version 2:
Effect: CrAn25 Create a swarm of spiders
Base 5, +1 Touch, +1 Concentration, +2 Group
Item maintains concentration: +5

In both versions, the creator must have a CrAn Lab Total above 30 to create the device, and the enchantment requires three pawns of vis to instill, but the second version allows for the spiders to exist past sunset/rise, provided that the person opening the box concentrates for a moment. Also, both versions produce a group of spiders with a mass equivalent to ten standard ponies. (This is a seriously huge number of spiders...)
Do I have this correct?

If we change the effect of version 1 to CrAn(Pe)35, the spiders would be poisonous, inflicting light wounds. The question here is how many bites would be inflicted by the swarm? If the effect were changed to create wasps, would it need the Pe requisite?

Do you really want it to work once per day, or would you rather do a charged item?

Nope, "Effects ... to wear off at sunrise or sunset ..." Unless you meant concentrate at sunrise/sunset, but I don't see anyone opening this would want to keep the surprise alive.

You don't need Perdo for poisonous spiders, those exist naturally. You might for an unnaturally strong poison but not in this case.

Moreover, I have vague memories of spiders being vermins, in which case you'd need CrAu or whatever medium that spontaneously creates them.

I... hope not. :unamused:

Just as creating "an insect" (Base 5) doesn't give you an insect the size of a small pony, Group shouldn't do the equivalent imo, the "Individual" size and Group rules notwithstanding.

Time to make a house rule then, because this is definitely what RAW says.

On that same page, the spell Curse of the Ravenous Swarm describes explicitly how these rules are applied for locusts, in the same way as Archimedes's effect for spiders.

Yes, I agree here - you'd get 'thousands and thousands of tiny spiders'. If I were the magus creating this, I'd want bigger spiders so their bite can actually penetrate human skin (there are very few naturally occuring spiders that can bite people - and Tarantulas aren't available unless your saga is set in South America), or really big spiders who can bite through armour. 10 pony-sized giant spiders should which case you'd want them to expire and not be indefinite in duration ("Yes, Your Holiness, this is the body of the giant spider-demon that killed Bob. Should we burn down the evil magicians?").

Multiple uses per day/charges would make sense too. Take it on adventures (add a rego req so the spiders will attack the right targets eg whoever the box is pointed at. Diameter duration so they don't get to run amok for too long) and you have an instant army. Enough uses per day, and you can hit every enemy with 10 giant spiders each...Parma will stop them hitting hermetic magi. Of course, making pony-sized dogs instead of spiders will lead to the magus getting a less evil reputation amongst survivors...


I love this item, would make a terribly scary combat spell too.

For combat a spell that creates a swarm of cat sized spiders would be sufficient to punch through skin and cloth, while a handy trap that summons swarms of normal sized spiders could be fun.

The great thing about this if you are an animal specialist is that with a simple increase of a single magnitude you can bump up the quantity by a factor of 10. So +1 size would give you an amount equal to 100 ponies. Thats a lot of ponies, let a lone a lot of spiders.

For sheer horror, a talented magus could whack a few size magnitudes on it and get the mass of 1000 ponies (+2 size) or 10,000 ponies (+3 size). Thats a lot of spiders, quite sufficient to drown or crush someone in a closed environment such as a library, lab or sanctum.

Tarentula is at first a mythic creature coming from Tarente region in south of Italy, it poisonous bite was giving a deadly lethargic state which could be countered by a fast dance, the tarentella (even if the name is from the XVIIth, it exists before with another name).
That mythic spider (which can also be found in the labyrinth of Creta) has given its name to the spider discovered in south america.
As mythic animals exists in Ars Magica, the Tarentula exist in south of italy, but probably with a might as it should be a magic beast
the beast is magic or faeric, the medecine (dancing tarentella) is probably faeric.

I will so be stealing this idea :slight_smile:

Isn't there something about not being able to create "magical creatures" with just Animal, or is that a diff edition?

Also, I'd suggest that if you're going to create spiders larger than "insect sized", the Base would become larger. That, at least, makes some sense given the Base guidelines.

Definitely, to both. :wink:

Thanks for the thoughts.
I was looking at Curse of the Ravenous Swarm for guidance on this one, and I am disinclined to HR the group size just yet. My troupe seems to prefer discussing effects that will make a good scene, and hand-waving exact sizes anyway.
The idea of making it a charged item is really interesting. It makes me think that instead of opening the box, the trigger is attempting to close the box :imp:

I've got three versions now:

  1. For the ick factor:
    Spider Box
    Effect: CrAn30 Create a swarm of spiders
    Base 5, +1 Touch, +2 Sun, +2 Group

  2. For something to use on your enemies
    Wasp Box
    Effect: CrAn25 Create a swarm of wasps
    Base 5, +1 Touch, +1 Diameter, +2 Group
    I am thinking a Sta stress roll of 12+ to avoid incapacitation due to the stings (this is a lot of wasps, and WebMD suggests getting medical attention for more than 10-20 stings), with a botch meaning the victim has died.

  3. Just because
    Box o' Badgers :smiley:
    Effect: CrAn40 Create a swarm of badgers
    Base 15, +1 Touch, +2 Sun, +2 Group

As a ST I'd look the victim in the eye, roll a bunch of hidden dice, and announce that she has run free but now has 287 Light Wounds :slight_smile: Just Light Wounds, mind you, but recovery is going to be a bitch.

Look at the ReAn spell in Art & Academe.

This is a bit more of a powerful spell needed, but creates natural spiders. So give them a spell command to bite and attack, they'll individually do nothing, but a Magus' Parma is NOTHING next to 10 individuals worth of spiders. Spiders small enough to ignore armour and Parma.


How big is this box? It would have to be a pretty big box to have 10 ponies worth of spiders in it at one time. As I understand it, normally Creo Magic creates something. This box seems to be envisioned to be continuously creating spiders until the size limit had been reached. I would think that would at least merit an additional magnitude for complexity.

What does small enough to ignore Parma mean? If magical water won't get someone wet through Parma, how in the heck are magically created spiders supposed to get through Parma?

I don't know :slight_smile:.

Size has nothing to do with it. Notice the word natural - Spiders are vermin, and as such arise spontaneously from relevant matter, like bees from dead cows. Thus the rego spell generates (not "creates", maybe "causes") spiders that are in no way magical, and thus not resisted by Parma.
Silly? I think so, but if Spiders are vermin (and they probably are, noble's Parma), then it works.

Either you use a control command and they will attack, and thus this is magically controlled, thus resisted, either you don't, and then they won't attack because spiders don't naturally bite people, even in huge number. They prefer to flee and find darkness.

=> must penetrate. Easy.

I could certainly be wrong, but I think it means that mssr. AW does not receive an "A" in composition today.

I think(?) his argument goes as follows:

  1. that, according to A&A, Rego magic can "cause" the natural generation of mundane spiders* (in the same way that flies are "naturally generated" from dead bodies, etc).
  2. that spiders are small enough to ignore armour.
  3. that they also (being "natural") ignore Parma.
    (* If so, this would be the equiv of any mundane item created via Rego-Craft. A Rego'd arrow is not a "magical" arrow, etc.)
    Besides EK's point re "non-attack-trained spiders", the obvious (ahem) problem with this is as follows: if you were to create a "box of bees", you would first have to have a dead cow inside the box, for that "natural generation" to occur, since Rego requires the "raw materials" (it's not "Creo"). So first show me how spiders, as vermin, are spontaneously generated, and then drop that into the box - then (according to A&A?) it could work. (Maybe.)

Cuchulainshound is actually spot on my meaning, and defence of my composition, using prozeugma (or at least trying and failing to) at quarter to 2 in the morning does not really work as well as one would hope.

I have reread this and Worms are Vermin, and spiders are worms of the air. Therefore they are sumonable by rego so this 'change' is natural and not resisted by parma. The rego effect to inflict the urge to go for nibbles is magical (and resistable) but the spiders have no resistance. This would actually not be that bad a spell by the account of the school of Vilano.


LoH has rules for swarms on p44, used for scorpions (probably at least as dangerous as wasps).

Basically, is has stats as a single creature, can attack a number of creatures equal to the swarm's size, but may "regenerate", and potentially ignore some weapons (such as swords).
A scorpion swarm of size +1 has Init +8, Attack +9, Def +3, Damage +3, their venom being treated as an asp's bite (Arm p 180): Stamina ease factor 9 to avoid an incapaciting wound.

Definitely less lethal, but IMO more interesting