Tricky rules question - time sensitive

[Abraham Z]

Hi all,

I'm GM-ing a game on Play by Post and something has come up that I would appreciate some rules insight from y'all. One PC is a psychic who is flying and has just cast greater invisibility. We've already had some discussions of this FAQ which makes it plain that even psychic spells have visible manifestations (so you know that a psychic spell has been cast, even though it has no verbal or spoken components), but now that he has cast greater invisibility, I'm unsure how that affects this, if at all. Specifically, if one of my NPCs (who does not have see invisibility, or any other way to locate the invisible psychic) were to ready an action to shoot at him as soon as he begins casting, would that work? Given that the psychic isn't saying anything or making any gestures to cast a spell, and he himself is invisible, what would be the basis (if there is one) for saying that my NPC's readied action is triggered? I suppose I could say that the air begins to shimmer as the magic is beginning to be enacted? Of course I understand that the psychic will remain invisible even if the readied action triggers, and as such will have a 50% miss chance, but I'm trying to understand if I have a basis for allowing the NPC to ready an action to interrupt spell-casting in this way (and, I should say, the NPC saw him turn invisible, so he's well aware that there is an invisible caster floating around).

Based on the linked FAQ above, I'm inclined to allow it but I expect the player to complain so I wanted to see what y'all have to say. 

If I don't allow it, this one PC could literally solo the entire encounter with a bunch of wands of magic missile and could just plink plink plink until the NPCs were destroyed, but I understand that sometimes that's just how it is in Pathfinder. 

What do y'all think? I'm avoiding posting about this on the main paizo site since the players at the table might well be reading.

thanks,
Abraham

[Jon]

A visible manifestation, is like shooting a flare in the darkness or the brief flash in a well lit room? I would say the flash will enable to zero on the area of the room the person is in and may degrade the plus 20 bonus since he wasn't standing still and is not incorporeal. He took an action and his breathing my have changed as he focused for the spell.

[Syrinx]

I would require some kind of Perception check for the NPC to be able to identify the square. The "manifestation" that a psychic spell creates is undefined, as is the interaction with Invisibility. But the intent seems clear to me that they want Psychic casting to be just as noticeable as normal casting. As a result, I would use the same mechanics requiring Perception that I have seen used many times before Psychics existed. Generally a DC 20 +1 per 10 feet away for noticing an invisible creature that isn't stealthing. As a GM that's what I would expect the PC's to have to do in order to pinpoint the location of an invisible NPC spellcaster, and it seems that should be the same ruling in reverse (regardless of Psychic or not). I might make it an easier DC by saying magic is particularly noticeable, but that seems like jerk move to me.

And of course, as you mentioned, you'd still apply the normal 50% miss chance as well.

Assuming you are in a 7-11 (minimum 8th level for a psychic to cast Greater Invis) I would argue that it would be hard for a PC to solo an encounter just using magic missile wands protected only by a rounds per level spell. Your NPC could potentially use the terrain to his advantage to narrow down the places the invisible PC could effect him from, but in general I'd just target someone else in the party, and let them suffer from their fellow party member's selfishness of going Invisible.

[Daniel H]

I mostly agree with Chris. I feel like if you rule it the way you were suggesting that basically defeats the purpose of both invisibility spells and see invisibility. Greater Invisibility is better than Displacement, if you just let anyone automatically know where a caster is because the caster used a spell while invisible, then Greater Invis serves no purpose.

They need to make a perception check to pinpoint the square the invisible person is in, and if they stealthed as they moved that check is probably impossible. Manifestations aren't some catch all that overwrites any effect that hides someone. It's just a mechanic that's there to explain why psychic casters still trigger AoOs for casting when they're just staring at people in funny ways.

And to sell Ultimate Intrigue since it has a feat that lets you hide manifestations.

[Abraham Z]

Thanks for the input, very helpful. My NPC rolled a 44 on her perception so she pinpointed him and made an AoO. She hit and beat the miss chance. She has grab - do I have to roll the miss chance again for the grab, or is it all part of the single AoO?

[Doonamis]

Single AOO. Octopus hits you with a tentacle. It gets to try its suckers on you since it hit you. Alligator bites you, it gets to try and grab as part of the bite. It's not part of a different attack.

[Abraham Z]

Ok, one player has just pointed out (this is in a PbP game) that you can't take an AoO against someone with total concealment. Does this gibe with y'all's understanding? Does he still have total concealment even when my Perception score has pinpointed him?

[Andrew Roberts]

A creature can generally notice the presence of an active invisible creature within 30 feet with a DC 20 Perception check. The observer gains a hunch that "something's there" but can't see it or target it accurately with an attack. It's practically impossible (+20 DC) to pinpoint an invisible creature's location with a Perception check. Even once a character has pinpointed the square that contains an invisible creature, the creature still benefits from total concealment (50% miss chance). There are a number of modifiers that can be applied to this DC if the invisible creature is moving or engaged in a noisy activity.

Link

[Abraham Z]

Yeah, so it goes. Darned Pathfinders!

[liamfisher]

You can make a standard action attack against them if you can find them, but not an AOO. If I could do that, there'd be a lot more dead pathfinders.