A strange and dangerous spell, although there are times when having a fire which burns while wet might be very handy. The original lasted for as long as the caster concentrated which makes sense as a demonstration of the transformation, but not as a true device of dangerous and unnatural fire. The spell is more dangerous than converting water to oil, as so many other water sources may be present which are uncontrolled.
Muto Ignem / Aquam 20, R: Voice, D: Sun, T: Individual
This spell changes a fire of a size up to bonfire so it unnaturally consumes water as fuel, as though it were oil or wood. The fire would be particularly dangerous in a wet forest, or on a marsh, and could be used to actually burn a river.
(Base 4, +2 Voice, +2 Sun)
Over 550+ new spells for Ars Magica can be found here.
What is intended by the term “unnatural” material in Ars Magica’s magic system, with regard to Creo of unnatural items? Well a long while back the 5e line editor clarified the intent, and I found it the other day while reading a tangential forum post.
David Chart wrote:
The intent was for “unnatural” to have the same meaning in all guidelines. You can Creo flammable water. However, since it isn’t natural, you can’t use vis to make it endure; it’s only sustained by the magic, like Muto. There is no form for it; that’s what makes it unnatural. It wasn’t written as requiring a Muto requisite because you aren’t changing anything; you are bringing something into existence with those properties. Looking at it now, the magnitude boost is probably too small, however.
I don’t think this got heavily playtested, because looking at the rules shows that they aren’t as clear as they should be. That probably indicates that I and all the playtesters thought that the meaning was perfectly clear, without actually agreeing on what that meaning was. But since no-one saw a problem, no-one raised it for discussion.
Great answer and fair enough. Considering the implications of this statement, they directly match to the behaviour of spell effects that are traditionally in the purview of Muto, but also may be performed with Creo with an increase in spell level. IMHO Creo was never restricted to only creating things that were “real”, as we know when spells can create mythical creatures and all sorts of wonderful things outside a peasant’s mindset.
This does give Creo a wider scope than I first thought though to give it, which is a nice enhancement to it’s role intertwined amongst the 5x techniques.