[OOC: A pure Creo Imaginem effect wouldn't need to penetrate to be seen, no (and it hurting people is a bit of a moot point).
I was thinking of the potential alternative approach of Muto Imaginem-ing Alcimus, which still wouldn't need to penetrate to be seen, but which I think would need to penetrate for him to attack someone with magic resistance for the same reason invisible characters need to penetrate.]
[OOC: Hmm. So potential alternative approach which solves the problem of being able to drop the spell at will:
Fray casts the Muto Imaginem spell as concentration duration (so, Base 3 + 1 Touch + 1 Conc = level 5)
Stephen then casts "Maintaining Another's Demanding Spell" on the Muto Imaginem spell (guideline will effect a spell with a level less than or equal to 1/2 *(base level + 5 magnitudes), so base 1 for a level 5 spell, +1 Touch + 3 Moon = Level 5.
Stephen uses his Harnessed Magic to cancel Maintaining Another's Demanding Spell at will later.
My understanding is that there's two different ways you can approach it:
The default, and what I'd been thinking of: You cast the Muto Imaginem spell on the target (i.e. Alcimus) emitting the species. The target is then under a magical effect, but the species are natural. The end result is that the species don't need to penetrate to be seen, but you do need to penetrate the magic resistance of the target to affect them in the first place.
You cast the Muto Imaginem spell directly on the species. In this case the species would be under a magical effect, and would have to penetrate to be seen. This option would probably also limit the mobility of the thing emitting the species.
[OOC: An illusion doesn't normally have to penetrate to be seen (although you do need to penetrate the magic resistance, if any, of the person you're transforming the image of - otherwise you could give random archmagi donkey's ears. If only once). However, it's possible to do it a non-standard way. See page 63 of HoH:S.]
Stephen will need to volunteer the information about his ability to cancel his spells at will, as I don't think Gregorius is aware he has harnessed magic. Gregorius will be publically trying to work out a way to reliably cancel the spell, so there's plenty of triggers to volunteer, assuming he's happy to.
Assuming this all gets agreed, Gregorius' plan is:
Build a secure pen to keep the horse in in case we end up capturing it.
Persuade Alcimus to agree to the plan. This should be fairly doable as it stands - it's only an illusion rather than an actual transformation, and he gets to spring the trap, so it's just magically enhanced hunting really. Gregorius has instructed him that they're not looking to get the horse dead, just unable to run away.
We go out to somewhere the aura's only Magic 1 (which there's plenty of available land to do).
Fray casts the Muto Imaginem spell as concentration duration (so, Base 3 + 1 Touch + 1 Conc = level 5), to transform Alcimus' sight, sound and smell.
Stephen then casts "Maintaining Another's Demanding Spell" on the Muto Imaginem spell (guideline will effect a spell with a level less than or equal to 1/2 *(base level + 5 magnitudes), so base 1 for a level 5 spell, +1 Touch + 3 Moon = Level 5. (Rego 20 + Vi 5 + Sta 2 + Aura 1 + W&G 2 + die)/2 = (30 + die) /2
Stephen makes everyone other than Alcimus invisible, and his boat invisible, then we all go and hover above Alcimus in one of the places the villagers were getting horses stolen from and wait for the horse to show up.
Hope the horse turns up before we all get too bored (and Fray needs to get back to his labwork). Gregorius will have brought water, and something to do, but is assuming the horse will turn up in the day time and we don't need to bother staking out at night.
When the horse turns up, do some combination of threaten, persuade and bargain with it into not stealing mares in future. Hopefully having had one said mare turn into a monstrous wolf will be an incentive in this regard.
Gregorius will bring Damianos and Theodoric as grogs. Damianos is good with horses, and Theodoric can translate if necessary. They've both brought bows.
A stallion that turns up and trys to lure away (or even magically spirit away) the fine mare that Alcimus should appear to be once Fray has finished with him. I'm not aware that the villagers have a more specific description than that, which is part of why Gregorius was going for plan "Set a trap" rather than "Go out and look for it".
Going down your list, I'm going to assume that building the secure pen is reasonably simple, unless you want to add magical protections to it. That makes convincing Alcimus the next step.
[OOC: How do you want to do Gregorius' conversation with Alcimus? Whilst he's designed as a companion, I've mostly been playing him myself.]
Gregorius will find Alcimus.
"I'm sorry I've had to leave you behind on my last couple of missions, Alcimus." The huge wolf understands (and is somewhat amused by) his effect on humans, but that didn't mean he liked Gregorius going away for weeks on his own.
"I need your help, now, though. How do you feel about springing an ambush? It does involve pretending to be a horse for a while, but it'll only be an illusion, not a shapechanging spell."
For the most part, I don't mind you playing him, but of course the SG has the last word in a case like this. What's your sense of how he'd fell about the role?
[OOC: The key issue is his Pride flaw, which doesn't sit great with pretending to be a mare to honey-trap a horse. However, it is only a minor flaw, and Gregorius has been trying to set things up to be relatively palatable (as him hunting the horse, rather than acting as bait). He's a
So overall, he'll probably go with it, reluctantly - he's loyal to Gregorius, who needs him to, but Gregorius is going to owe him, even if not formally.]
Presumably Gregorius knows from his conversation with the village which lands it is that they are wanting the covenant's protection to graze on, so definitely within those.
Other than that, he will talk to Damianos (who has Animal Handling 5 plus a speciality in horses) about where in that area is prime grazing land, and pick somewhere that seems suitable.
Damianos explains that horses tend to like wide open areas, where they can see predators coming from some distance away--mind you, finding a hiding place in such a spot might be difficult. Of course, horses also like to drink, and so spots next to water could also work, and there are certainly locations along the river nearby where the horses come to drink.
Finding a hiding place shouldn't be an issue, as we can just use the invisible flying boat again (although would be good to have a bit of rougher ground/vegetation nearby to hover over so the shadow isn't obvious in bright sunlight). We can use the trick of turning the boat invisible with everyone off it, then turning people invisible using individual spells to avoid warping.
Once we've found a spot, I think we're now onto spell casting - Gregorius' understanding of the plan is:
Fray casts the Muto Imaginem spell as concentration duration (so, Base 3 + 1 Touch + 1 Conc = level 5), to transform Alcimus' sight, sound and smell into that of a fine mare (size +1, but so are most of the local horses).
Stephen then casts "Maintaining Another's Demanding Spell" on the Muto Imaginem spell (guideline will effect a spell with a level less than or equal to 1/2 *(base level + 5 magnitudes), so base 1 for a level 5 spell, +1 Touch + 3 Moon = Level 5. (Rego 20 + Vi 5 + Sta 2 + Aura 1 + W&G 2 + die)/2 = (30 + die) /2
It isn't a quick process...it takes a day and a half for a stallion to appear. He comes tantalizingly close...only to be spooked by something at the last minute, and to gallup away as if demons were chasing him.
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