One of the players in my heavily customized Mistridge saga is playing a Bjornaer magi with a barn owl for his Heartbeast, and has expressed his intention to create, as his first lab project, a cloak of owl feathers that changes shape with him, fusing with the feathers of his body in owl shape and instantly recovering its cloak shape when he turns to human again. (He called it his own "unstable molecule suit"). Since all my players are new to Ars Magica, I helped him to design the following item. It is the first item I design, so I'm posting it here so my more experienced and rules-savvy sodales can critique or point out the flaws in the design that I'm surely missing. Is this the best way to create such an item? What other options could be used?
Mantle of Owl Feathers
This heavy woolen mantle is lined with thousands of owl feathers on the outside. If worn by a shapeshifter able to become an owl of any kind, it becomes part of the bird's plumage at the moment of the transformation, and reverts to mantle form when the wearer becomes human again.
From Mantle to Plumage (MuAn 19)
From Plumage to Mantle (MuAn 19)
Base: 5. The Muto Animal guidelines (p. 118) indicate a base of 5 to change something made from animal products in a major and unnatural way. I used this since the new shape has to become integrated into the owl's plumage or viceversa.
Range: Personal (+0, the item casts both effecs on itself)
Target: Individual (+0)
Duration: Sun (+2, 2 uses/day +4 levels). This would give each effect a constant duration as long it is activated. Each effect would be triggered by the wearer's shapeshifting
This results in two different effects of level 19 each. Does it seem correct?
You don't need both effects. To revert back to the natural form of the object is simply a case of cancelling the active enchantment; a second effect is not required.
Chances are the owner wants to be able to cancel the enchantment. As such, I would suggest instead of sun duration, an effect of concentration duration with the added 'item maintains concentration' effect. This has a very similar effect to sun duration, except the owner can shut down the effect whenever they want.
If the owner wants to be able to activate this more often than once per day, I'd suggest a few more levels in uses-per-day. Unlimited is probably overkill.
The item has no trigger-effect, which means it needs to be activated independently of the heartbeast transformation.
The final result isn't that the item merges with the magus, but it becomes a still-distinct object that resembles plumage and is 'worn' by the owl. It would require vastly more complicated magics to have it actually merge with the form of the caster.
Having the item automatically transform with the heartbeast transformation would mean having some kind of intellego magic in the item so it knows when to do the transformation. This is starting to look unnecessarily complex; if it's essentially a woolen cloak, I'd not worry. I'd instead do something like:
Mantle to Cloth Ring
Transforms a heavy wollen mantle into a small loop of cloth; small enough to wrap around the leg of a bird.
The final level probably won't be that bad (MuAn 5, +0 personal, +5 concentration, +5 item maintains, +5 many uses/day) - a single MuAn20 effect. It won't transform automatically with the heartbeast, and should the spell ever get cancelled it'll revert back to the form of a woolen cloak.
I've seen a variety of solutions to this particular problem; a common one is to invest a 'create me some cloths' effect into a talisman. Others have gone with a combination of CrIg and CrIm to keep themselves warm and provide the appearance of clothes. It largely depends on the arts of the magus.
I don't agree with that. Both MuCo spell p131 (Shape of the Woodland Prowler and Cloak of the Black Feather) includes a cape of some sort, which does merge with the target (it is not explicitely mentionned, but neither the bird- nor the wolf-shaped man is hindered by the cloack - hence my interpretation of the spell). But there is a Animalem requisit.
In this case, since it works only when the target turn into an Animal form, the requisit would be... Animalem to allow the cape to fuse with the owner. So no change in the spell base level, just in the description of the effect.
Or you can add an small InCo with constant effect (base: 4 - sense a very general information about a body: are you human ? +1 (touch) +2 sun: 15 +4 for 2 use/day + automatic trigger).
Then you need to add a link effect to the main enchantment, and probably increase the use/day.
So it becomes a major magical item and will cost a lot more virtus, whereas the proposal of Kid Gloves could be done as a minor magical item with some degree of specialisation (let's say an aura of +5, a decent lab for a young magus (+1), +2 Int, + 4 MT, selection of a proper focus for another +4, that 16, 24 to go for Te+Fo+ possibly some appropriate bonus). Not for every young magus, but doable by specialist or more senior magus.
On purpose, I did not factor in all specilisations a lab can have since we are talking about young magus, as it is his first lab project,
+4 is 2 uses a day (+1) and an environmental trigger (+3)
InCo effects on the item are problematic for two reasons:
warping due to constant effect
penetration, because Parma
This rapidly starts looking like a Real(tm) project; simply requiring the user to activate the item independently is considerably less effort.
Probably worth noting that a 'more senior magus' for the simple version doesn't mean a senior magus, just one who doesn't still have that fresh-Gauntlet smell. 5 years post-Gauntlet would probably be plenty assuming this is a desired goal.
I was pretty sure that I was overcomplicating some aspects of the item while completely missing others
I like the idea of a simpler item with pretty much the same effect. Concentration maintained by the item seems certainly the way to go, and lowering the complexity by making it user-activated is also a good idea, even if it is not exactly what the player wanted.
I am inclined to allow the fusing of the mantle into the owl's plumage without altering the effect's level, since it is a mostly cosmetic effect and, as Ezechiel357 pointed out, there is some precedent to it.
Otherwise, I will follow your suggestions and make it a MuAn 20 effect, with 24 uses/day and concentration maintained by the item. A cloth mantle has a capacity of 4 vis, so it leaves room for another 20 levels of effects if the player decides to upgrade it in the future.
Something worth noting: triggering an enchantment takes the character's action, but a Bjornaer changing form does not (according to HoH:MC). The player can therefore change form and trigger this item in a single round, but has to remember to do so -- it is not automatic.
Also, because the Duration is Concentration, he will have to concentrate for a round at sunset and sunrise to maintain the effect.
HoH:MC describes an enchantment called Perceive the Change, which constantly monitors the wearer's shape and triggers the shapechanging power of the enchantment (through a linked trigger) when the wearer activates his heartbeast. This would be truly automatic; the disadvantage is that it incurs a warping point every year for being under a constant enchantment. Of course, you could avoid that if you don't wear the invested item all the time, which would be true under many circumstances -- a feather cloak for example might not be worn around the lab or when studying, but only donned when going abroad.
I had a Bjornaer with a rook heartbeast in my campaign create a very similar item. It was his talisman, so he made it out of his own feathers, which he collected for several years as he molted until he had enough.
I would also add that this kind of very practical and useful enchantments must have been invented by many Bjornaer magi, for all kind of shapes and size of animal. Inlcuding variant with or without the automatic transformation with the trigger spell.
So if the magus has some good connections with other Bjornaers, and his lab total does not allow him to invest the effect in one single season, acquiring some labtot should not be expensive. It is not unlikely that House Bjornaer could have a few of those spells written more clearly than lab notes by their author and could be willing to lend (for free or minor cost) such text lab.