Sage Advice - 2015/11/16

[DanyBallon]

Sage Advice for november 2015 (http://dnd.wizards.com/articles/features/rules-answers-november-2015)

[GWJ_DanyBoy]

It's not a good sign when my first thought, before even reading the article mind you, is "Oh great, now what have they messed up?".

Edit: Oh my god, these guys kill me. "An unarmed strike isn’t a weapon...", then in the next point "an unarmed strike is a melee weapon attack". Super intuitive and consistent as always Sage Advice.

[Maxilian]

They didn't really say anything new or anything we did not know so... meeehhh

[DanyBallon]

I find this month rulings some kind of no brainers, maybe except for the unarmed is not a weapon, but unarmed strike is a melee weapon attack. I guess we'll get use to it, because unarmed strike text say so. :smallbiggrin:

[Gwendol]

Nice to see that when attacking with a shield (even as an improvised weapon) you still retain the bonus to AC.

All in all, not a very contentious set of rulings. We also get (further) confirmation that the wood elf and lightfoot halfling racial trait are in fact variants of HiPS.

[EvanescentHero]

There are a lot of things from Sage Advice that I do intend to follow, but a monk/rogue not being able to get Sneak Attack from their unarmed strikes isn't one of them. That breaks absolutely nothing, so I don't see the problem.

Nice to know that you can shield bash and retain your AC bonus though!

[Temperjoke]

It's not a good sign when my first thought, before even reading the article mind you, is "Oh great, now what have they messed up?".

Edit: Oh my god, these guys kill me. "An unarmed strike isn’t a weapon...", then in the next point "an unarmed strike is a melee weapon attack". Super intuitive and consistent as always Sage Advice.

Well, unarmed strikes aren't a specific weapon, but an unarmed strike is a type of attack that falls into the melee weapon category of attacks, in case spells or defenses make a difference between the types.

[Maxilian]

There are a lot of things from Sage Advice that I do intend to follow, but a monk/rogue not being able to get Sneak Attack from their unarmed strikes isn't one of them. That breaks absolutely nothing, so I don't see the problem.

Nice to know that you can shield bash and retain your AC bonus though!

Well it gives the Rogue way more chances to make SA, but is true it doesn't break anything (still... IMHO everyone knew that already but still people like to add homebrew rules)

[EvanescentHero]

Well it gives the Rogue way more chances to make SA, but is true it doesn't break anything (still... IMHO everyone knew that already but still people like to add homebrew rules)

Oh no, this class gets to use its main class feature more often. =P I'm not too worried about it, honestly. Multiclassing should let you use interesting class feature combinations, in my opinion, as long as they're not busted.

[krugaan]

apparently, "melee weapon attack" != an "attack" with a "melee weapon"

either that or the word "finesse" is missing, which is much more likely.

[CNagy]

Hmm... the only thing I disagree with there is the ruling on the shield. Armor proficiencies are not weapon proficiencies, so right now the only way to be proficient in the offensive damaging-dealing use of a shield is to be a Tavern Brawler. And the image I get from Tavern Brawler is someone grabbing a shield with both hands and swinging it at someone, or grabbing it by the straps one-handed and smacking someone in the face.

How did a professional and practiced attack with the shield get left out of the rules? Having to piece it together from existing rules is very inelegant. You want to have a good shield bash that isn't your primary weapon? Take Tavern Brawler, take Dual Wielder, take the Two Weapon Fighting Style--two feats and a style so that you can get a 1d4+Str bonus action attack and +3 AC. Two feats--required--makes it pretty much Fighter only, no?

The first bullet point of Shield Master should be changed; "You gain proficiency in the use of a shield as a weapon, which deals 1d4 bludgeoning damage and is considered to have the Light property." Then you amend Two Weapon Fighting so that it is just "When you take the attack action to attack with a light weapon in one hand..." instead of "...and attack" in order to allow the bonus action attack with the shield to come first. The fact that you can use that bonus action to shove is already baked right into the rules. Boom. Done. No strange feat taxes--just the one feat that you expect to have to take to use the shield for offense in the first place.

Then if you want to use a wider range of weapons with the shield, you can get Dual Wielder for the same reason that you would normally get Dual Wielder.

[Maxilian]

Oh no, this class gets to use its main class feature more often. =P I'm not too worried about it, honestly. Multiclassing should let you use interesting class feature combinations, in my opinion, as long as they're not busted.

Yeah i know, i just pointed out that even if it doesn't break anything we all knew that it wasn't RAW, but also... we all know that the rules are mere guides

Note: Also... it doesn't let them use their feature more often, its just make them more likely to hit (well... you could say that this does mean that you can use it more often cause its less likely for you to end your round without hitting someone :smallbiggrin: )

[Maxilian]

apparently, "melee weapon attack" != an "attack" with a "melee weapon"

either that or the word "finesse" is missing, which is much more likely.

That's the case for Unarmed Attack, you can make a melee weapon attack with your fist, but they are not a weapon

[Theodoxus]

Hmm... the only thing I disagree with there is the ruling on the shield. Armor proficiencies are not weapon proficiencies, so right now the only way to be proficient in the offensive damaging-dealing use of a shield is to be a Tavern Brawler. And the image I get from Tavern Brawler is someone grabbing a shield with both hands and swinging it at someone, or grabbing it by the straps one-handed and smacking someone in the face.

How did a professional and practiced attack with the shield get left out of the rules? Having to piece it together from existing rules is very inelegant. You want to have a good shield bash that isn't your primary weapon? Take Tavern Brawler, take Dual Wielder, take the Two Weapon Fighting Style--two feats and a style so that you can get a 1d4+Str bonus action attack and +3 AC. Two feats--required--makes it pretty much Fighter only, no?

The first bullet point of Shield Master should be changed; "You gain proficiency in the use of a shield as a weapon, which deals 1d4 bludgeoning damage and is considered to have the Light property." Then you amend Two Weapon Fighting so that it is just "When you take the attack action to attack with a light weapon in one hand..." instead of "...and attack" in order to allow the bonus action attack with the shield to come first. The fact that you can use that bonus action to shove is already baked right into the rules. Boom. Done. No strange feat taxes--just the one feat that you expect to have to take to use the shield for offense in the first place.

Then if you want to use a wider range of weapons with the shield, you can get Dual Wielder for the same reason that you would normally get Dual Wielder.

As a huge fan of shield bashing in games, I approve of this homebrew. We already have precedence for a feat granted bonus 1d4 attack without going through improvised attack shenanigans, so why not another 'master' feat? If it wasn't for the way Shieldmaster allows the user to emulate the classic Paladin reflecting the red dragon breath off his shield, I'd be ok with dropping the evasion lite aspect to the feat in favor for a damaging shield bash... but I don't think adding the damage component (especially if it's a bonus attack, and provides an either/or aspect to pushing or damage (not both)) makes the feat op as it stands.

S&B needs a boost. This would do it :)

[Tanarii]

Most important thing I see here affects Assassins, making it clear they only get one round of automatic critical with their attacks, and they have to win the initiative to get it:

A surprised creature can’t move or take an action or a reaction until its first first turn ends (remember that being unable to take an action also means you can’t take a bonus action). In effect, a surprised creature skips its first turn in a fight. Once that turn ends, the creature is no longer surprised.

The unarmed is a melee weapon attack, but not a (melee) weapon, is nothing new. It's a continuation of prior rulings and the PHB errata that removed it from the weapons table.

[EvanescentHero]

Yeah i know, i just pointed out that even if it doesn't break anything we all knew that it wasn't RAW, but also... we all know that the rules are mere guides

Note: Also... it doesn't let them use their feature more often, its just make them more likely to hit (well... you could say that this does mean that you can use it more often cause its less likely for you to end your round without hitting someone :smallbiggrin: )

By more often, I actually meant with more weapons and more styles, not more actual times. =P But yeah, the extra attacks you can make as a monk would make it easier for you to land a sneak attack with your fists.

[Sigreid]

Nothing in this that will change how I run the game. Where my rulings differ from theirs, I'll just continue to ignore theirs.

[SharkForce]

i find it pretty unlikely that these are the questions most in need of answers. i mean, sure, nice to know, but really? a couple of them are practically identical to previous questions. the rest i think have already been answered on twitter anyways.

as far as i can tell, they answered the one question about planar binding that did not need any clarification in the slightest. almost every other part of using the damn spell is clear as mud, and they answered a question about whether the (abjuration school) spell summons anything when the spell discusses needing to separately summon a target into a magic circle, and what happens if the target was summoned using another spell...

they answered next to nothing, and the questions they did answer are not questions that need official clarification to be clear. what a wasted opportunity to actually provide some meaningful clarifications.

[Malifice]

Hmm... the only thing I disagree with there is the ruling on the shield. Armor proficiencies are not weapon proficiencies, so right now the only way to be proficient in the offensive damaging-dealing use of a shield is to be a Tavern Brawler. And the image I get from Tavern Brawler is someone grabbing a shield with both hands and swinging it at someone, or grabbing it by the straps one-handed and smacking someone in the face.

Anyone can shield bash. Only a person with Tavern Brawler can add profficiency to the attack roll.

This surprised me the most:


Do the lightfoot halfling and wood elf hiding racial traits allow them to hide while observed? The lightfoot halfling and wood elf traits—Naturally Stealthy and Mask of the Wild—allow members of those subraces to try to hide in their special circumstances even when observers are nearby. Normally, you can’t hide from someone if you’re in full view. A lightfoot halfling, though, can try to vanish behind a creature that is at least one size larger, and a wood elf can try to hide simply by being in heavy rain, mist, falling snow, foliage, or similar natural phenomena.

Worded cautiously (doesnt expressly say 'under observation' only 'when observers are nearby' but the intent seems pretty clear. Looks like those traits (in addtion to changing 'what' you can hide behind) also allow one to attempt to hide even under direct observation as a 'Hide in plain sight' type ability.

Looks like halflings and wood elves can remove object permanence after all.

[Tanarii]

This surprised me the most:



Worded cautiously (doesnt expressly say 'under observation' only 'when observers are nearby' but the intent seems pretty clear. Looks like those traits (in addtion to changing 'what' you can hide behind) also allow one to attempt to hide even under direct observation as a 'Hide in plain sight' type ability.

Looks like halflings and wood elves can remove object permanence after all.
I just assume they dodged the "observed" thing because "closely observed" doesn't mean what you interpret it to mean. :p

Just teasing. Kinda. But I did notice that the answer very clearly sidestepped the huge part of the question as phrased: what does "closely observed" or even just "observed" actually mean? And how does it interact with Stealth, exactly? Is pop-up stealth legal, and under what circumstances?

[Malifice]

I just assume they dodged the "observed" thing because "closely observed" doesn't mean what you interpret it to mean. :p

Just teasing. Kinda. But I did notice that the answer very clearly sidestepped the huge part of the question as phrased: what does "closely observed" or even just "observed" actually mean? And how does it interact with Stealth, exactly? Is pop-up stealth legal, and under what circumstances?

Same. Intentional IMO. They wanted to leave enough wriggle room for a DM to say 'No'.

'When observers are nearby' - Not: 'While under observation.'

That said, the intent does seem to be that halflings and wood elves can hide perfectly fine in combat as long as the specified terrain is nearby, and they are under anything less than direct observation.

If I'm watching a halfling he can't duck behind Harry the fighter and hide. But if I'm distracted (say... on account of Grog the half-orc barbarian trying to stave my face in with a greataxe) it's fair game.

[Sigreid]

Anyone can shield bash. Only a person with Tavern Brawler can add profficiency to the attack roll.

This surprised me the most:



Worded cautiously (doesnt expressly say 'under observation' only 'when observers are nearby' but the intent seems pretty clear. Looks like those traits (in addtion to changing 'what' you can hide behind) also allow one to attempt to hide even under direct observation as a 'Hide in plain sight' type ability.

Looks like halflings and wood elves can remove object permanence after all.

I don't know. Didn't they describe the wood elf fading into the mist as if nature itself was trying to hide him? I took it to mean these two specific cases get a spooky ninja vanishing act. YRMV

[Tanarii]

@malafice for sure. They generally seem to keep flexible play & table rules in mind. Even when it can cause a bit of confusion for us. :)

But I think you're wrong, it pretty clearly says these races *can* use Stealth while behind directly observed. "It’s as if nature itself cloaks a wood elf from prying eyes—even eyes staring right at the elf!"

Now obviously from your perspective, that's a direct rules change.

Really this just makes me wonder what the hell the PHB errata on "see you clearly" was supposed to accomplish. Before that, it seemed fairly straight forward: any creature could hide with heavy obscured/total cover, elves with lightly obscured, and halflings with creature cover. To me, this SA seems in line with that. But the errata can be taken to imply any creature can hide with any obscured or cover, making the elf/halflings ability useless.

Honestly, the best middle ground to me seems to be: any creature can start hiding with total cover or heavy concealment, but can maintain it with less (can't clearly be seen) after that point. Wood elves can start with naturally occurring light obscured. Halflings with creature cover.

That still won't work with your anti-popup way of running it ... On the first round. But it would if you used that set of rules for after the first round. Everybody except wood elves and light 1/2ling need to get totally out of sight, then check next round. Those two can meet their special requirements (ie they're actually seen), but still can't check until next round.

[Malifice]

I think you're wrong, it pretty clearly says these races *can* use Stealth while behind directly observed.

I agree that the intent seems to be that observation doesnt cancel the Hide attempt. Im just positing that the wording was left open (intentionally in my view).


Really this just makes me wonder what the hell the PHB errata on "see you clearly" was supposed to accomplish. Before that, it seemed fairly straight forward: any creature could hide with heavy obscured/total cover, elves with lightly obscured, and halflings with creature cover. To me, this SA seems in line with that. But the errata can be taken to imply any creature can hide with any obscured or cover, making the elf/halflings ability useless.

Because attempting to Hide is a two step process.

Its the start of your turn and you want to hide from an Ogre.

Step 1: Can you be seen clearly? If the answer is 'yes', you can't attempt to Hide on your turn. If the Ogre is looking at you, you cant run over to a box, jump in and close the lid, and attempt the Hide action. He knows exactly where you are.
Step 2: If you can't be seen clearly, you can move into your box and attempt to Hide. He wasnt watching you go into your hiding spot, and now doesnt know where you are (although he can probably guess with some degree of certainty if there is only the one box in the room).

Looks like Elves and Halflings can pretty much avoid step 1 in any scenario in which they find themselves behind their special terrain that triggers their special aility.

So a Halfling that was already behind a M sized creature and not hiding, can attempt to Hide. A Wood elf that is fighting in a forest can also attempt to Hide.

[CNagy]

Anyone can shield bash. Only a person with Tavern Brawler can add profficiency to the attack roll.

That would be why I said it was the only way to be proficient, yeah. But how are you going to shield bash? Take your attack action to do it? With shove it makes sense: you are trading possible damage for doing something tactical. With a straight-up bash, you're basically saying "I'd just rather do one attack in my sequence that is 1d4+Str rather than 1d8+Str." Longsword, shield bash, longsword goes the 11th level Fighter for no discernible reason.

If you want it as a bonus action, that'll be another feat please. Dual Wielding drives the feat count up to two, and now the 11th level Fighter goes longsword, longsword, longsword, bonus action shield bash. Two feats for a 1d4 damage bonus action attack that doesn't get an ability bonus to damage unless that fighter also invests in a fighting style.

That's a really steep price for something that should be mostly available (all but the off-hand ability bonus damage) in the Shield Master feat.

[SharkForce]

the stealth ruling probably has some implications for the skulker feat as well.

[Malifice]

But how are you going to shield bash?

The Attack action. Its a melee weapon attack with an improvised weapon.


Take your attack action to do it? With shove it makes sense: you are trading possible damage for doing something tactical. With a straight-up bash, you're basically saying "I'd just rather do one attack in my sequence that is 1d4+Str rather than 1d8+Str." Longsword, shield bash, longsword goes the 11th level Fighter for no discernible reason.

Alternatively, have your shield made out of mithril or some other light material, and ask your DM if that is enough for it to be considered a 'light' improvised weapon (or ask first before getting it crafted as such).


That's a really steep price for something that should be mostly available (all but the off-hand ability bonus damage) in the Shield Master feat.

I agree. For what it offers its subpar to (polearm master+GWM+protection) in everything aside from the AC.

[Vogonjeltz]

They didn't really say anything new or anything we did not know so... meeehhh

Sage advice is pretty much intended for two groups of people:
1) People with poor reading comprehension skills
and
2) Anyone who has to deal with the people in group 1.

[tsotate]

Anyone can shield bash. Only a person with Tavern Brawler can add profficiency to the attack roll.

Or a bladelock whose pact blade is currently a spiked shield.

[huttj509]

If I'm watching a halfling he can't duck behind Harry the fighter and hide. But if I'm distracted (say... on account of Grog the half-orc barbarian trying to stave my face in with a greataxe) it's fair game.

Halflings have toddler skills.

"crud, I blinked, where'd he go?"

[Vogonjeltz]

the stealth ruling probably has some implications for the skulker feat as well.

It doesn't seem so, all three allowed a character to attempt to hide in certain lightly obscured circumstances (a person, natural phenomena, or all). The SA didn't make a ruling there, it just answered the query.

[Mr.Moron]

A lightfoot halfling, though, can try to vanish behind a creature that is at least one size larger, and a wood elf can try to hide simply by being in heavy rain, mist, falling snow, foliage, or similar natural phenomena. It’s as if nature itself cloaks a wood elf from prying eyes—even eyes staring right at the elf! Both subraces are capable of hiding in situations unavailable to most other creatures, but neither subrace’s hiding attempt is assured of success; a Dexterity (Stealth) check is required as normal, and an observant foe might later spot a hidden halfling or elf: “I see you behind that guard, you tricksy halfling!”

The rule is now clear! Finally the debates can end. Though this is does make for some very funny situations:

Halfing in a featureless 5ftx5ft room with 6 humans:

1 Human stands in the center of the room, and gets on all fours.
The other 5 stand around him a circle.
Halfling declares he is hiding using the center human crawls under him (now partially obscured from all by the center human's torso) and rolls above their passive perception scores (let's say they share a score of 12). No one person in that room has any idea where the halfing went.

Still it's good to know where the RAI stands, at any rate. I'm content to house rule it away to play as I always have because I personally find it ultra-silly and ultra-powerful, but it's nice to have some baseline clarity.

[Malifice]

The rule is now clear! Finally the debates can end. Though this is does make for some very funny situations:

Halfing in a featureless 5ftx5ft room with 6 humans:

1 Human stands in the center of the room, and gets on all fours.
The other 5 stand around him a circle.
Halfling declares he is hiding using the center human crawls under him (now partially obscured from all by the center human's torso) and rolls above their passive perception scores (let's say they share a score of 12). No one person in that room has any idea where the halfing went.

Still it's good to know where the RAI stands, at any rate. I'm content to house rule it away to play as I always have because I personally find it ultra-silly and ultra-powerful, but it's nice to have some baseline clarity.

They avoided saying the Halfing can hide while under direct observation. So those humans in the circle would still need to be distracted (looking the other way).

[DanyBallon]

The rule is now clear! Finally the debates can end. Though this is does make for some very funny situations:

Halfing in a featureless 5ftx5ft room with 6 humans:

1 Human stands in the center of the room, and gets on all fours.
The other 5 stand around him a circle.
Halfling declares he is hiding using the center human crawls under him (now partially obscured from all by the center human's torso) and rolls above their passive perception scores (let's say they share a score of 12). No one person in that room has any idea where the halfing went.

Still it's good to know where the RAI stands, at any rate. I'm content to house rule it away to play as I always have because I personally find it ultra-silly and ultra-powerful, but it's nice to have some baseline clarity.

As Malifice said, they need to be distracted, so it may more end up like this:

Halfing says "look up! A dragon"
Humans look up - nothing
Humans wants to confront the halfling "where's that little bugger gone"

In such a relative close space they shouln't take long to find him out, but with a good stealth score he could pull it out.

[MrStabby]

Going back to the shield bash thing - is the shield then considered a weapon as an improvised weapon? Is it considered a weapon even if you do not use it as such?

For example can duelist fighting style work with a weapon and a shield if the shield is an improvised weapon? Can you use the damage bonus but only on the weapon and not on the bash? Can you use the damage bonus but only on turns where you don't bash with the shield? If the second would you extend the bonus to other offhand weapons - if you are two weapon fighting but opt not to make a bonus action attack you could use the dueling style?

[Tanarii]

They avoided saying the Halfing can hide while under direct observation. So those humans in the circle would still need to be distracted (looking the other way).

Are you trying to claim that just because the specific example for "eyes staring right at" was for the wood elf, the halfling can't hide when being looked at directly? The previous sentence says "A lightfoot halfling, though, can try to vanish behind a creature that is at least one size larger".

You're reading what he's talking about completely wrong. In both cases the PC is being observed. In the first, the PC is moves and is acting. It vanishes. In the second, the wood elf stands still ... It fades from view. He's not "avoiding" anything. He's being explicit. Both abilities work while under observation.

[Malifice]

Are you trying to claim that just because the specific example for "eyes staring right at" was for the wood elf, the halfling can't hide when being looked at directly? The previous sentence says "A lightfoot halfling, though, can try to vanish behind a creature that is at least one size larger".

'Eyes staring right at' refers to the state of events after the hide attempt. Not before.

A Wood elf hides behind a ficus in the corner. I cant watch him do it, but if he does it, I cant see him anymore.

Read:


Do the lightfoot halfling and wood elf hiding racial traits allow them to hide while observed? The lightfoot halfling and wood elf traits—Naturally Stealthy and Mask of the Wild—do allow members of those subraces to try to hide in their special circumstances even when observers are nearby. Normally, you can’t hide from someone if you’re in full view. A lightfoot halfling, though, can try to vanish behind a creature that is at least one size larger, and a wood elf can try to hide simply by being in heavy rain, mist, falling snow, foliage, or similar natural phenomena. It’s as if nature itself cloaks a wood elf from prying eyes—even eyes staring right at the elf! Both subraces are capable of hiding in situations unavailable to most other creatures, but neither subrace’s hiding attempt is assured of success; a Dexterity (Stealth) check is required as normal, and an observant foe might later spot a hidden halfling or elf: “I see you behind that guard, you tricksy halfling!”


You're reading what he's talking about completely wrong. In both cases the PC is being observed.

No, he doesnt say that at all. The exact quote is: [these traits] allow members of those subraces to try to hide in their special circumstances even when observers are nearby.

Not 'allow them to hide while being observed'.

The comments about being hidden despite being in plain view of the enemy (theyre just standing behind a ficus) is just reiterating what we already knew they can do.

If a Wood Elf is standing 10' away from you in the rain and youre looking right at him he cant use mask of the wild to just vanish. If you turn away, he can. Assuming he beats your passive perception score, you can no longer see him anymore despite him being in plain view of you.


In the first, the PC is moves and is acting. It vanishes. In the second, the wood elf stands still ... It fades from view. He's not "avoiding" anything. He's being explicit. Both abilities work while under observation.

No, it says nothing about 'fading from view'. The elf doesnt melt into falling snow as you observe him, nor does he 'unmelt' if you actively scan for him (take the search action) and spot him (roll higher in your perception check than his stealth result.

You turn away and the elf hides behind the falling snow. You turn back and can no longer see him. You scan the snow for him and beat his stealth check result and realise that he's been in front o you standing behind falling snow the whole time.

Imagine it like one of those magic eye 3D images, or spotting a chameleon on a tree.

If you watch the chameleon intentily it cant hide from you. If you turn away from it, it can hide from you, despite being in plain sight of where you are.


For example can duelist fighting style work with a weapon and a shield if the shield is an improvised weapon?

Not if you use the shield as a weapon. If you weild a weapon in your off hand you cant claim the duelling bonus.

If you hold a heavy stick or broken bottle in your off hand, you can claim the dueling bonus. If you attack with the stick or bottle, you cant claim the +2 dueling bonus with the sword in your other hand (and vice versa).

[CNagy]

Also nowhere does it say that hiding is accompanied by a feeblemind effect that has afflicted creatures going "Uhh... where did he go, George?" If a Halfling manages to vanish from view under a person while being watched by other people, those people have a pretty good idea of where the Halfing is. They don't "know" in the strictest sense; magic could be at work, or some kind of tricksy trap door, but if another guy came into the room and said "where is the Halfling?" the humans would point to the guy the Halfling disappeared under. In the case of creatures who can vanish while still observed, you obviously remember where you last saw them and can draw rational conclusions on where they might be if there isn't much cover in the area. You can't target them with spells that require targets you can see, and even if you make a melee attack on the right spot you still have disadvantage to hit.

The difference between being seen and being seen clearly, to me, is illustrated to great effect in the movie Predator. Dutch has just pulled himself out of the water and onto the muddy bank when the Predator hits the water behind him. He scrambles up the bank, getting covered in mud in the process, and then presses his back to the root bed of an overturned tree or something. The Predator comes out of the water, looking for Dutch, but the human lucks out--the Predator is using thermal vision and the mud is masking Dutch's body heat. Dutch is not unseen; there is an unbroken line of sight between him and the Predator. But he is not clearly seen; the Predator does not realize that what he is looking at is actually a person covered in mud and pressed against the tree roots. The errata clearly refers to someone who is already hiding, so being seen but not clearly is not a situation where you can hide--people can already see you. What it does do it allow a creature to remain hidden even if a creature wanders over to a spot where it could have seen him when he wasn't hidden, like through less dense foliage or fog. You couldn't hide in those conditions, but you can remain hidden--perhaps the creature sees your form but mistakes you for a large rock, a bush, whatever. That's different than hiding behind a wall and having a creature wander over to your side of the wall--it's not going to mistake you for a piece of masonry. And that's why the DM decides which circumstances are appropriate.

Normally, you need to be heavily obscured in order to hide. Coming back to Dutch, he hid (unbeknownst to him) against the root bed while the Predator was still underwater. His movement wasn't observed, at the time there was no direct line of sight. For the Halfling and the Wood Elf, they can hide while lightly or partially obscured. You see the Wood Elf in the fog and then it vanishes from view. You see the Lightfoot sidestep behind the fighter and suddenly you don't see any sign of him. In both cases, the first place you are going to look is the last place you saw them. Depending on circumstances, you may or may not find them. Circling around the Fighter means that the Halfling is no longer obscured by him (if he hasn't moved since Hiding) and thus is likely discovered. Moving to the spot where you last saw the Wood Elf might not reveal him--perhaps he moved away once he was out of sight. Perhaps he didn't move away so much as up, and he is wedged between two trees just above your eye-line. The DM determines the circumstances that are appropriate.

Edit: An observer is a nearby observer rather than a nearby creature because he is observing the Elf or Halfling in question. You see them, but they are partially obscured and that partial obscurity is enough for them to take an action to try and vanish from sight.

[Malifice]

]Also nowhere does it say that hiding is accompanied by a feeblemind effect that has afflicted creatures going "Uhh... where did he go, George?" If a Halfling manages to vanish from view under a person while being watched by other people, those people have a pretty good idea of where the Halfing is. They don't "know" in the strictest sense; magic could be at work, or some kind of tricksy trap door, but if another guy came into the room and said "where is the Halfling?" the humans would point to the guy the Halfling disappeared under. In the case of creatures who can vanish while still observed, you obviously remember where you last saw them and can draw rational conclusions on where they might be if there isn't much cover in the area. You can't target them with spells that require targets you can see, and even if you make a melee attack on the right spot you still have disadvantage to hit.

No, its like a chameleon.

If you watch it in a tree closely, it cant hide from you. If you are distracted and lose track of it (looking away) it can attempt to Hide from you even though it is in plain sight of where you are. You would need to search for it to see it again.

So you cant target it with spells, or attacks (barring a lucky guess with the latter) until you can see it again. You literally no longer know where it is, despite it being in plain view of you.

It cant do this while you're directly observing it.

Imagine if this bloke:

http://www.diyreport.com/wp-content/uploads/2014/07/camouflage-shape.jpg

...was standing right in front of you, and you were staring straight at him (like you are right not). He is not hidden from you.

If you looked the other way for a second or two, and he moved elsewhere (quietly) and hid, he suddenly is hidden from you, even though you can probably still actually see him.

You can see something and not percieve it or notice it. Theyre different things. Its kind of how I imagine the Wood Elf ability to work. They can still be seen (a 5' 8" Elf hiding behind a 3' tall ficus) you just no longer notice them. They cant 'melt away' into a ficus shape while you keep tabs on them, but if you get distracted they certainly can hide in plain sight of you.

It'd be kind of spooky if one person was watching him and others werent.

Dude 1: 'Where did the Elf go?
Dude 2: He's over there in the corner, 5 feet away, behind the ficus.
Dude 1: What? That 3 foot little sapling. No he's not!
Dude 2: Yeah man he totally is.
Dude 1: [squints and looks closer, taking the search action,rolling well] Oh yeah... there he is.
Dude 3: [walks over to the ficus looking intently, but flubbing the perception check] Nah, I cant see him.
Dude 1: Just pick up the ficus!
Dude 3: [Lifts up the three foot pot plant and instantly spots the nearly 6 foot tall elf hiding behind it] - Holy crap! How did you do that!