Invisibility - what point during an attack do you become visible?

[Thurbane]

A situation arose in last night’s play I am a little unclear on:

The party wizard, who was invisible, cast an attacking spell (magic missile) which rendered her visible. Two of the enemy had readied an action, to fire crossbows against anyone casting a spell.

The question is this: since the wizard only became visible on casting the magic missile, do the crossbow shots still hit quickly enough to have a chance of disrupting the spell?

 

[shilsen]

No. The wizard only becomes visible after he casts the spell. So by the time the shots are taken, the spell has been cast.

 

[Dross]

My timeline = the mage finishes casting, the missles appear and fly to their target, the wizard appears and then the missles hit their target. This seems to fit in with casting a non attacking spell (think of flare as a signal or trying to blind someone with the spell, Invisibility needs to know what the wizard is doing)

Slightly off topic: Does the ready action actually go off since the Xbowers don't SEE the wizard cast?

 

[sukael]

My timeline = the mage finishes casting, the missles appear and fly to their target, the wizard appears and then the missles hit their target. This seems to fit in with casting a non attacking spell (think of flare as a signal or trying to blind someone with the spell, Invisibility needs to know what the wizard is doing)

Slightly off topic: Does the ready action actually go off since the Xbowers don't SEE the wizard cast?

Except that using magic missile is always a violent act, since it can only ever target creatures. I'd personally say that the wizard appears the same moment the missiles start shooting--as they're already been made, it's too late to interrupt the spell.

Technically, the ready action goes off, since the crossbowmen saw a spell effect, but no casting. I'd let it work in this case, though, to target the obvious source of the spell effect.

 

[RigaMortus2]

Except that using magic missile is always a violent act, since it can only ever target creatures. I'd personally say that the wizard appears the same moment the missiles start shooting--as they're already been made, it's too late to interrupt the spell.

Technically, the ready action goes off, since the crossbowmen saw a spell effect, but no casting. I'd let it work in this case, though, to target the obvious source of the spell effect.

So what do you think happens if a Wizard casts magic missle at a door? Does the spell still go off and get used up with no effect? Does the spell fail, but still count as being used? Or, since the door is an invalid target to begin with, does the spell not go off and not get used up?

 

[Thurbane]

I ruled that the crossbowmen still had a chance to disrupt the casting...looks like I may have judged in error...

(As it happens, the wizard made her concentration check anyway)

 

[sukael]

So what do you think happens if a Wizard casts magic missle at a door? Does the spell still go off and get used up with no effect? Does the spell fail, but still count as being used? Or, since the door is an invalid target to begin with, does the spell not go off and not get used up?

A wizard cannot, by the definition of the spell, cast magic missile at a door. What happens when there are no viable targets is a longstanding bit of debate, though.

 

[Vegepygmy]

The question is this: since the wizard only became visible on casting the magic missile, do the crossbow shots still hit quickly enough to have a chance of disrupting the spell?

No. The spell must have been completed for the attack to occur, and the attack must have already occurred for the invisibility to end. Otherwise, rogues would not be able to use invisibility to set up sneak attacks, since they would become visible before completing the attack.

 

[Dross]

Except that using magic missile is always a violent act, since it can only ever target creatures. I'd personally say that the wizard appears the same moment the missiles start shooting--as they're already been made, it's too late to interrupt the spell.

Technically, the ready action goes off, since the crossbowmen saw a spell effect, but no casting. I'd let it work in this case, though, to target the obvious source of the spell effect.

Which is why I bought up the flare example. While YMMV with a spell that can only be used for a violent act, I feel my answer is consistent to handle all cases in the same way, not differently for different modes of spells.

 

[Jhulae]

A situation arose in last night’s play I am a little unclear on:

The party wizard, who was invisible, cast an attacking spell (magic missile) which rendered her visible. Two of the enemy had readied an action, to fire crossbows against anyone casting a spell.

The question is this: since the wizard only became visible on casting the magic missile, do the crossbow shots still hit quickly enough to have a chance of disrupting the spell?

As others have said, the wizard would have become visible after finishing the casting of her spell.

However, based on the described readied actions for the enemies, they should have taken their shots at the invisible caster (and either fully missing if they had no clue where she was, or with the 50% miss chance if they made a reactionary spot check versus DC 20+ to notice where she was).