# Opportunity attacks vs. invisible enemies?



## Zerakon (Mar 22, 2009)

I'm curious to know if there's rules that should inform how I adjudicate attacks vs. invisible enemies. I've read the sections of the PHB on invisible and opportunity attacks but I might have missed something, and certainly might have missed an official ruling elsewhere.

Examples (assuming the PC cannot see invisible creatures):

1) A visible creature begins his turn adjacent to a PC. It first uses an action to turn invisible. Then it moves away. Does the PC get an opportunity attack? Is there some perception vs. stealth roll that needs to happen for the OA to occur? Or do you automatically receive the OA but at -5 for total concealment?

2) A visible creature begins his turn a few squares away from a PC. It first uses an action to turn invisible. Then it moves past (and adjacent to) the PC. Does the PC get an opportunity attack? Is there some perception vs. stealth roll that needs to be successful for the OA to occur?


----------



## Oompa (Mar 22, 2009)

*Page 281:

Invisible Creatures and Stealth: If an invisible creature is hidden from you (“Stealth,” page 188), you can neither hear nor see it, and you have to guess what space it occupies. If an invisible creature is not hidden from you, you can hear it or sense some other sign of its presence and therefore know what space it occupies, although you still can’t see it. 

*So simply said..

If an invisible creature has not made a stealth check, you know in which square it is when it moves near you.. So you can get OA only with a penalty

*On your turn, you can make a Perception check as a minor action (page 186) to try to determine the location of an invisible creature that is hidden from you.*

So conclusion, if an invisible creature is not hidden, you sense it's location, but can't see it. If a invisible creature is hidden, you have no clue where it is so it can sneak past you if it has a greater stealth check than your passive..


----------



## DracoSuave (Mar 22, 2009)

It's easy.

You only get opportunity attacks against creatures you can see.


----------



## Zerakon (Mar 22, 2009)

After looking again at the rules on pg 290 of PHB, I definitely agree with Draco and disagree with Oompa. What I missed earlier was the phrase "and you can see your enemy" at the end of the "Able to Attack" bullet.


----------



## chitzk0i (Mar 22, 2009)

Check the updated rules as reprinted in the PHB2.  They make it clear that you could make an OA (at -5 for total concealment) against an invisible creature that _hasn't_ made a stealth check.


----------



## abyssaldeath (Mar 22, 2009)

chitzk0i, those are the rules for targeting what you can't see(general rule). OA's have their own rules and the rules for OA's say that you need to see the target(specific rule).


----------



## Regicide (Mar 22, 2009)

chitzk0i said:


> Check the updated rules as reprinted in the PHB2.  They make it clear that you could make an OA (at -5 for total concealment) against an invisible creature that _hasn't_ made a stealth check.




  I don't see anything overriding the requirement in OA of being able to see the target, nor do I see the -5 rule.


----------



## Tellerve (Mar 22, 2009)

If someone is invisible but hasn't made a successful stealth check against you then while you can't "see" him you know he is present and in which square (maybe his body pushes some of the leaves away from him in the forest, or his boots displaces water in a creek, or you see his footprints, or the dust roils about his invisible form).  However, he still has total concealment, hence the -5 to your attack.  So there's your rules, nice and easy and just how the Errata had them.


----------



## Mort_Q (Mar 22, 2009)

Even if you are aware of an invisible enemy, you still can't _see_ it.  The rules of OAs clearly state that you can not make and opportunity attack if you can not _see_ the enemy.   

You can still attack the enemy, on your own turn, if you spend a minor action to perform a perception check... etc.


----------



## webrunner (Mar 22, 2009)

Mort_Q said:


> Even if you are aware of an invisible enemy, you still can't _see_ it.  The rules of OAs clearly state that you can not make and opportunity attack if you can not _see_ the enemy.
> 
> You can still attack the enemy, on your own turn, if you spend a minor action to perform a perception check... etc.




Just a note: you dont need to do the perception check to attack an enemy who didn't use stealth, even if they are invisible.  The perception check just lets you find the square, but without a stealth (or with a failed stealth) you already know the square.


----------



## Tellerve (Mar 23, 2009)

This is where it is getting too nitpicky with the definitions I fear.  See is what they wrote, but you can "see" where the invisible guy is in the square.  Would you not allow an AO for a human at dusk when a goblin moves by him?  Of course you would, at least I hope you would.  The goblin has partial concealment.  The invisible goblin has total concealment but since he hasn't passed his stealth check you know what square he is in and where he was moving, and instead of the partial concealment of dusk, you take the total concealment of invisibility (-5).

On your turn you don't need to make a minor action for the perception check.  In fact, as long as the invisible enemy isn't trying to be stealthy then there is no need as you can clearly tell which square he is in by the rules in phb2.  Using the minor perception would be if you loose him because he uses stealth on you and you loose which square he is in.  Either way it is still -5 to hit him, so save your minor action.


----------



## Oompa (Mar 23, 2009)

*Phb 273 Seeing and Targeting:

*To determine whether you can see a target, pick a corner of your space and
trace an imaginary line from that corner to any part of the target’s space. You can see
the target if at least one line doesn’t pass through or touch an object or an effect—such as a wall, a thick curtain, or a cloud of fog—that blocks your vision.

--

So if i know where a creature is, i can effectively check if i can 'see' it..


----------



## Regicide (Mar 23, 2009)

Oompa said:


> *Phb 273 Seeing and Targeting:
> *So if i know where a creature is, i can effectively check if i can 'see' it..




  No, you can check if there is any terrain blocking you from seeing it.  This has nothing to do with invisibility.

PHB 281
INVISIBLE
-You can’t be seen by normal forms of vision.
-You have combat advantage against any enemy that can’t see you.
-You don’t provoke opportunity attacks from enemies that can’t see you.

  In two places in the PHB, both OA and Invisibility rules clearly state that you can't OA people that you can't see.  What the heck?


----------



## AngryPurpleCyclops (Mar 23, 2009)

Regicide said:


> No, you can check if there is any terrain blocking you from seeing it.  This has nothing to do with invisibility.
> 
> PHB 281
> INVISIBLE
> ...



Seems pretty clear to me as well.  It might have been played wrong in our game though because heavily obscured is only -2 if you're adjacent.


----------



## AbdulAlhazred (Mar 23, 2009)

Yeah, it is absolutely clear, invisibility makes you IMMUNE to OAs. Being hidden has nothing to do with it.

To make the other situations more clear, if someone is invisible and not hidden you know what square(s) they are in. Thus you can attack the square (-5 to hit), you don't need to make a perception check to do that. In fact there is NO benefit to making a perception check against a non-hidden invisible enemy.

If an enemy IS hidden and invisible then you can make a perception check, minor action, to overcome their stealth and determine which square(s) they are in. Once you do that you can attack them (again with a -5 to-hit penalty). At that point they ARE no longer hidden from you, although the hidden creature could subsequently move and hide again.

You can also ALWAYS target a square instead of a specific creature with an attack. It will be a -5 to-hit penalty. This is useful for playing "sub-search" with hidden invisible opponents, or opponents behind total cover. The DM should roll the to-hit in these cases and just tell the player if it was a hit or a miss so that the roll can't reveal whether or not there is even a target in the square (if not then the attack is an automatic miss, you don't want the player to know that). 

Pretty much all the same considerations apply to being hidden WITHOUT invisibility. Enemies can always target your square, though in general they will be simply guessing if you are there or not. OA is also not possible against a hidden target since being hidden means you are "invisible to the enemy". 

There is a slight ambiguity however. Suppose you are hidden next to an enemy and you move away. Moving more than 2 squares forces a new stealth check, but at the instant you start moving, you haven't yet moved (and might not even move 2 squares), so does the enemy get an OA? It isn't really clear. There are a few ways a DM could rule. 1) There is no possibility of an OA if you are moving less than 3 squares. 2) There is no possibility of an OA at all because you have not YET moved more than 2 squares. Furthermore does it depend on whether or not you are breaking cover? The gist of it is, at what point in your action do you become not hidden, and at what point in a move action where you move more than 2 squares do you become not hidden?


----------



## AngryPurpleCyclops (Mar 24, 2009)

I think the context of this post has to do with an encounter with many city guards who surrounded both our rogue and our fighter during different points during the encounter.  My wizard was behind a wall in a park and rather than let the guards just pummel our guys to death I moved stinking cloud on top of them thinking that taking damage from the cloud was way better than taking 4 OA.  This allowed the rogue to get up from prone and move away(without the subsequent OA's) from the 4 guards and it allowed our fighter to stay on his feet in the middle of 6 attackers.  

Upon reading the rules a couple times it looks to me like the rogue should have had to make a stealth roll in order to sneak out of the cloud without the OA's but the OA's should have been at -2 if they went off.  part of me thinks how we played it makes more sense than having OA's because being partly blinded and inhaling poison would probably prevent you from being very effective at OA's.


----------



## Zerakon (Mar 24, 2009)

AngryPurpleCyclops said:


> I think the context of this post has to do with an encounter with many city guards



Haha, uh, no.

I posted the original question about 9 hours before that encounter.

I was simply prepping myself for your eventual doom when you face invisible enemies. Muhahaha.


----------



## Regicide (Mar 24, 2009)

Zerakon said:


> I was simply prepping myself for your eventual doom when you face invisible enemies. Muhahaha.




  LOL!  In your FACE Melee Training feat!


----------



## GorTeX (Mar 24, 2009)

Tellerve said:


> This is where it is getting too nitpicky with the definitions I fear.  See is what they wrote, but you can "see" where the invisible guy is in the square..




No, you know where the invisible guy is, but you still do not see him, as he is invisible.


----------



## AbdulAlhazred (Mar 24, 2009)

GorTeX said:


> No, you know where the invisible guy is, but you still do not see him, as he is invisible.




Yup, exactly. And this is the main point of why invisibility is such a nice ability to have (well, besides making it a LOT easier to hide). Take away that advantage and really what all does invisibility do for you? It becomes just a debuff. Not BAD, but it was intended to prevent OA and balanced for that. Look at the difficulty in actually acquiring invisibility, especially invisibility that lasts anything past 1 round. This is also why monsters with special senses, like tremorsense, can be quite challenging, they aren't as restricted by visibility issues. If you nerf invisibility it would kind of reduce the value of those senses.


----------

