Handling invisible monsters

[jorrit]

Sometimes monsters have the ability to turn invisible (like say the Duergar scouts in Thunderspire Labyrinth). So as a DM you then remove the miniature from the map and remember (or write down) where it is. But what do you do if a player then decides to move and happens to move through or end at a position where the invisible creature is? Do you then stop the player and tell him or her that there is an invisible obstacle there? That seems to be the most sensible solution. I suppose the player can then try to target that tile with an attack (and -5 to the AR I believe).

A related question. What if a ranged attacker targets a visible creature but an invisible creature is between the ranger and the visible creature so in effect the arrow would never arrive at the visible creature. Not sure how to handle this.

Greetings and thanks,

 

[Black Knight Irios]

Sometimes monsters have the ability to turn invisible (like say the Duergar scouts in Thunderspire Labyrinth). So as a DM you then remove the miniature from the map and remember (or write down) where it is. But what do you do if a player then decides to move and happens to move through or end at a position where the invisible creature is? Do you then stop the player and tell him or her that there is an invisible obstacle there? That seems to be the most sensible solution. I suppose the player can then try to target that tile with an attack (and -5 to the AR I believe).

When a player uses stealth (successful) he is treated as invisible. If a monster moves into the square he occupies it auto detects the player, in this case he loses invis. (see stealth rules)
You use this rule and don't apply the part about invis breaking. The player knows the square but the target is still invis.

A related question. What if a ranged attacker targets a visible creature but an invisible creature is between the ranger and the visible creature so in effect the arrow would never arrive at the visible creature. Not sure how to handle this.

If the invisible creature is an enemy to the player it still provides cover for the target (invis =/= no substance). If the invis monster/object blocks Line of Effect (LoE) the attack fails, this could be possible in the case of a Gelatinous Cube. But it is in most cases up to the DM's ruling (the LoE part).

 

[deleteme123456]

If it blocks LoE I would allow the attack to automatically be redirected at the blocking creature with a -5 penalty for targetting what you can't see. I would also tell the player something like "your arrow seems to have stopped well short of the target, falling in this general area" (give a burst 1 centered on the invisible creature)

 

[ThirdWizard]

Are there any rules for using Perception to locate an invisible creature?

 

[Black Knight Irios]

Are there any rules for using Perception to locate an invisible creature?

PHB P281
The grey box at the bottom of the page.

 

[ThirdWizard]

PHB P281
The grey box at the bottom of the page.

Thanks!

I tend to overlook rules in insets for some reason.

 

[frankthedm]

But what do you do if a player then decides to move and happens to move through ... where the invisible creature is?

Depends what the Creature wants. If it want to remain invisible it lets the player through its space, not dissimilar to an ally letting a friend through their square. If it want to announce it's position and probably break invisibility, it takes an OA on the Player for moving through threatened area.

But what do you do if a player then decides to move and happens to ... end at a position where the invisible creature is?

The creature takes it's OA, whacking the player back into the last legal space the character occupied.

 

[Black Knight Irios]

Depends what the Creature wants. If it want to remain invisible it lets the player through its space, not dissimilar to an ally letting a friend through their square. If it want to announce it's position and probably break invisibility, it takes an OA on the Player for moving through threatened area.

I would say the creature needs to make a new stealth check with a penalty because it doesn't matter if your ally touches you as he moves through your square but the enemy should not touch you for obvious reasosn.

The creature takes it's OA, whacking the player back into the last legal space the character occupied.

The "whacking back" occurs regardless of a hit or miss on the OA because it is part of the movement rules and not of the attack.

 

[deleteme123456]

RAW, I don't think you can choose to allow an enemy to move through your space, so the invisible creature blocks movement "an invisible force blocks your way" or something, if you have movement left, continue. If the creature takes an OA, it will have to stealth again (assuming it's still invisible or otherwise has total concealment/superior cover), but I would also say the creature does not have to take the OA. The players know something is there, invisible, but maybe it's an object, not a creature.

 

[Smeelbo]

Be sure to carefully read the PHB Errata on Stealth. Hidden is not Invisible, and Invisible is not Hidden. How can this be so? Ask Stinky and Squeaky, who despite being Invisible, are easily located.

The short version: Even if you are Invisible, unless you are also Hidden, characters know your location. Invisible characters have Total Concealment, so they are hard to hit (-5 penalty to attack), and can become Hidden by making a Stealth check at the end of a move action.

Smeelbo