Returning to Ars Magica after a few years, I am toying around with a bonisagus character concept with some fae heritage, and I have a simple idea for a spell he might want to invent.
Basically, the idea is to use Muto Mentem to transform a thought into a magical effect. I don't remember having seen any comparable effect in the book but I may be wrong.
Obviously, such an effect could really mess the game, and one could simply argue that this should not be possible, given that this is precisely what spontaneous magic is all about. While this is fair from a balance point of view, and receivable (but discutable imho) from a lore perspective, I see nothing in the limit of hermetic magic which could forbid such a feat. Also, I find the idea quite funny and I like some design challenge. So I've tried to design a spell guideline to cover the effect. I'm a curious as to what some of the most experienced players here think.
The premises on which I based my reasoning are the following :
- there is a spell guideline under muto mentem which states that one could turn a thought solid by a MuMe effect of base level 25, which seems like a good starting point. Turning a thought to magic should be at least as difficult as turning it solid.
- Muto Vim guidelines effects are usually designed to be specific to one form, so it seems reasonable that the same constraint should apply here. More generally, muto spells usually transform the target into a specific category of individuals. So it seems right that the Muto Mentem effect should have to be specific
- Muto Vim guidelines also specifies that a change in power of more than 2 magnitudes requires Creo or Perdo to create more magical energy or destroy some. Following this principle, it seems that Creo should always be required if one tried to turn a thought into a spell, as there is no magical energy to begin with
- the effect should not be an easy substitute for spontaneous magic, but it should provide some niche uses for a dedicated character
- the effect should have some limitations related to essential nature. A thought is an elusive phenomenon, ephemeral and difficult to maintain. This should provide an interesting ground to impose limitations on how it could be manipulated, both from a balance perspective, and in respect to the above point
- finally, using a spell to transform a thought into another spell effect is a very indirect way of working magic. This implies that the resulting effect could not benefit from any hermetic virtues or direct bonuses such as spell masteries as the magus is not directly casting the final effect. However, as it is still magic, it should come with all the risks associated, namely warping and twilight.
So, given all that, here is my proposition :
General: Turn a thought into a magical effect of a given form, of less than or equal to the (level - 4 magnitudes) of the Muto Mentem spell, with a Vim requisite. Turning a thought to a magical effect requires Creo to create the necessary magical energy : while Muto gives a pattern to the effect, Creo is essentially what fuels it.
The effect produced is designed as if it was casted by the target of the MuMe spell. If the target is trying to control the thought in order to produce a specific effect, she should make an intelligence + concentration roll against an ease factor of 12 + the magnitude of the desired magical effect. If the roll fails, the effect is still created, but the more the concentration roll is far off the ease factor, the more the effect will be different from what was expected. If the roll botches, the target must roll a number of botch dices equal to the magnitude of the produced effect and may gain warping points in the process. Note that these botch dices cannot be reduced by spell mastery or hermetic virtues as the target is not casting the spell, though the magical effect comes out of control.
A magical effect produced in this way is still essentially a thought, and as such, is very volatile by nature. Thus, its duration cannot be other than momentary or concentration. In the latter case, the effect may naturally change over time, at the storyguide's discretion, reflecting the vagabonding nature of the human mind. The target of the MuMe spell can push its concentration to maintain the form of the magical effect by making further concentration rolls each round she wants to fix the effect. Each failed roll transforms the effect (the new effect cannot be of higher level than the original) and cumulatively increases the ease factor of the next rolls by 1. The new effect retains some correspondance with the previous one: a cat may become a rat, which may become a swarm of insect, which may turn into an infectious disease. Note that for the effect to have a concentration duration, the Muto Mentem spell duration must allow the transformation to last more than a mere moment, and thus, must also have a duration of concentration or greater.
Magical effects obtained by transforming a thought have additional constraints related to their very nature :
- a thought may not be turned into a complex effect, ie. it cannot reproduce any spell with a modifier related to intricacy/complexity nor can it reproduce an effect which would require a ritual,
- the effect cannot reproduce the Intellego technique, as the target must be able to visualize the outcome of the effect in order for it to be materialized,
- the effect always have a penetration score of 0,
- the effect is an arcane connection to the target of the Muto Mentem spell, though this may never be an issue as the effect is very short lived,
- the effect cannot be targeted by MuVi spells designed to transform hermetic spells at time of casting, as again, the target is technically not casting a spell
For instance, a maga can turn the thought of a bird into a Creo Animal effect of level 20 (base 10, +1 touch, +1 concentration). This requires a Muto Mentem spell of level 45 with a Creo Vim requisite (base 40 in order to produce an effect of level 20, +1 concentration). She then must make a roll of intelligence + concentration againt an ease factor of 16 (12 + 4 magnitudes) in order to determine the result of the transformation. If the roll is failed by a slight margin, the effect could produce a cat smaller than normal, with a handicap, or an unusual gait. If the roll is failed by a large margin, the mind of the maga wanders from the original thought and the effect could produce another animal of similar size, the corpse of a cat, or something very different related to the original thought, like a statue of a small animal, the sound of a yowl, or a warm blanket. The maga can try to fix her thought in the next round, by making another concentration roll against an ease factor of 17.
WEAVE THE MAGICAL THOUGHT (FORM)
R: Per, D: Mom, T: Ind
Req: Creo, Vim
When casting this spell, the magus concentrates on a particular thought which is then made real as a magical effect of a given form. The resulting effect is designed as if the magus were casting the spell, and cannot be of level greater than 25. See the guideline for the limitations and mechanics of this effect. There are 10 versions of this spell, one for each form.
(base 45, +1 concentration)
In summary, in order to make the most of the effect, a character would have to put a high investment on Creo, Muto, Mentem and Vim, as well concentration, though the latter could be made easier by rego mentem. This would give him an alternative but limited way to improvise simple magical effects. Another interesting use would be to enchant an item to give companions a indirect way to work magic, for instance, a "wand of wishes" enchanted with Weave the magical thought (Imaginem) could allow a non gifted character to produce simple imaginem effects, provided that she has the mental abilities to fix her thoughts.
What you guys think ? Would you allow such an effect in your saga ? Despite its limitations, it may still be too strong and be an open door for exploit. If so, how would you rule it ?