Enemy with blindsight: how to

[The Shadowdove]

Hey folks,

I've ran games with monsters who have blindsight before, but it's coming up again and I want to be sure of the way it functions this time.

Also, there's a rogue in my players party this time. So it makes things a bit more specific.

1) What does blindsight negate?
2) does it penetrate any substances/objects?
3) how does it affect a stealthed character?
4) what are the advantages of having it?
5) are there any drawbacks/kryptonite?
6) any notes or interesting facts/ideas you're generous enough to impart upon me.

Thank you in advance

-dove

[gfishfunk]

1) What does blindsight negate?
2) does it penetrate any substances/objects?
3) how does it affect a stealthed character?
4) what are the advantages of having it?
5) are there any drawbacks/kryptonite?
6) any notes or interesting facts/ideas you're generous enough to impart upon me.

1. It only negates invisibility / low light conditions / darkness. The creature is hearing, smelling, or otherwise sensing. It is different from true sight because the thing does not 'see.'
2. No.
3. Stealth is as normal. If the creature is also blind, the stealth attempt can be in 'plain sight' for obvious reasons: sight is not an issue.
4. Creatures can sense stuff in total darkness, dim light conditions, and it can sense stuff that is invisible. It does not make the senses any stronger, however, unless it states so in the description. A lot of enemies will say something like 'the creature has advantage on checks relying on smell.' Also, if there is a source of darkness, the creature would not get disadvantage on attacks while being inside of it, or have advantage imposed on it. In fact, it will likely have advantage on attacks while in darkness.
5. Depends on how the creature gained blindsight. Hearing? Silence. Smell? Strong Odors of another kind or having targets downwind. Think through WHY the creature has blindsight in order to figure out how it can be overcome.
6. For fun, I like including a little special trap of magical flowers that (when stepped on) do a 6 second (1 round) 5' radius of magical darkness. They do no damage, but create darkness which is ignored by the blindsight creature.

[SharkForce]

we don't have a ton of RAW on these. answers are my personal rulings.

1) darkness, any gaseous substance that obscures vision (mist/fog/steam, smoke, poison fumes, etc)
2) only gas unless otherwise mentioned.
3) some forms of visual obscurement will not work (you won't be able to hide in a fog bank, for example).
4) mostly seeing in magical darkness and fog clouds. it isn't clear, but for things that require a creature to "see" a target, i allow blindsight to count but i wouldn't allow, say, using perception to know where a creature is.
5) potentially overconfidence/over-reliance on it, i suppose. otherwise, not really. i mean, if it's sound-based (as with a bat), silence spells, but that's a specific creature's blindsight, not blindsight in general.
6) that's about it, i'm afraid.

[RSP]

Though the RAW isn't clear, I believe Blindsight is intended to act as if the creature using it can "see" regardless of invisibility or lighting conditions.

Per the rule on Stealth, you cannot hide if you can be seen, so anyone attempting to hide from a creature with Blindsight would need to use cover to hide (as opposed to just walking out in the open).

For reference on this, here's a Crawford tweet on this (from the Sage Advice website):

@Aseahawkfan "Does Stealth or Invisibility work within Blindsight range?" A creature can try to hide within blindsight range behind cover.

[ClearlyTough69]

A creature with blindsight can ignore obscurement caused by invisibility, dim light or darkness within range of its blindsight. It can't see colour or shade. Everything else is unchanged.

Cover still blocks blindsight and material obscurement (caused by fog, foliage, snow or a dust storm) still obscures as it does normal sight.

I guess blindsight can see through illusions unless they specifically have a tactile component, but am not sure about that.

[Oramac]

I always figured blindsight functioned just like regular sight, except that a creature doesn't need eyes to use it. Gelatinous Cubes, for example.

[gfishfunk]

While a lot of this is true, definitely check the source of the blindsight. A gelatinous cube has some sort of magical sight. Some creatures are presented blindsight through acute senses.

[RSP]

The rules regarding blindsight do not change based on what reason is given for why the creature has blindsight.

Not saying don't houserule it as desired at your table (or that doing so wouldn't make sense), just clarifying for the OP that the RAW is regardless of the fluff.

[SharkForce]

The rules regarding blindsight do not change based on what reason is given for why the creature has blindsight.

Not saying don't houserule it as desired at your table (or that doing so wouldn't make sense), just clarifying for the OP that the RAW is regardless of the fluff.

not quite true. bat blindsight cannot see things in a silence spell, for example.

[RSP]

Yes, if something specifically states an exception to the rules, you should go with the stated exceptions.

Assuming in the bat write up it states something along the lines of "silence cancels out the bats blindsight," I'd follow those rules.

[SharkForce]

Yes, if something specifically states an exception to the rules, you should go with the stated exceptions.

Assuming in the bat write up it states something along the lines of "silence cancels out the bats blindsight," I'd follow those rules.

hmmm... double checked to be sure, and 5e is silent on the issue of silence... a deafened bat cannot use blindsight, and logically that should mean that it can't see things in a silence spell, but there isn't anything specific.

[gfishfunk]

Right, but this isn't a post on the RAW thread up top, so I think the better answer is to go an extra step on the rule for some logic and hijinks.

A bat relying on hearing for blindsight would think that a silenced area was empty and might slam into a wall there because the echo location doesn't echo back, thus it thinks nothing is there.

A wolf-like creature with blindsight based on smell would not care about cover, but being down wind would probably give advantage.

Magical blindsight would work like sight, so a gelatinous cube wouldn't see you behind cover but could see you in a pitch black room.

I think this makes more sense -- but at your table do your thing.

[BiPolar]

Right, but this isn't a post on the RAW thread up top, so I think the better answer is to go an extra step on the rule for some logic and hijinks.

A bat relying on hearing for blindsight would think that a silenced area was empty and might slam into a wall there because the echo location doesn't echo back, thus it thinks nothing is there.

A wolf-like creature with blindsight based on smell would not care about cover, but being down wind would probably give advantage.

Magical blindsight would work like sight, so a gelatinous cube wouldn't see you behind cover but could see you in a pitch black room.

I think this makes more sense -- but at your table do your thing.

I really like this - but what do you do in cases of either non-mundane or creatures that have blindsight but no stated method on what that blindsight is (like echolocation for bats)?

Sort of like a system of:
Pure Blindsight, non-mundane with no obvious system: Acts like Truesight/Tremorsense
Blindsight, but system stated: Penalties associated that are system dependent (like Echolocation and sound)

[gfishfunk]

I wouldn't adopt a uniform rule. Take a look at the creature, either guess at a justification or make one up, and then apply it to the group.

A dragon with blindsight might have powerful smelling or a magic sense. Make a decision and then be consistent with that dragon type. Then flag it to the players. "I..... Smell something..."

The main thing in my mind is not having a "good approach" but keying in the players so that they can interact with the feature meaningfully. That lets them plan and come up with cool ideas and makes the game enjoyable without giving them something on a silver platter.

[BiPolar]

I wouldn't adopt a uniform rule. Take a look at the creature, either guess at a justification or make one up, and then apply it to the group.

A dragon with blindsight might have powerful smelling or a magic sense. Make a decision and then be consistent with that dragon type. Then flag it to the players. "I..... Smell something..."

The main thing in my mind is not having a "good approach" but keying in the players so that they can interact with the feature meaningfully. That lets them plan and come up with cool ideas and makes the game enjoyable without giving them something on a silver platter.

definitely like it...many instances you can figure out fluff for how they sense with blindsight, but do you see examples where it does end up like truesight or is there always a hidden weakness? For instance, Helmed Horrors have blindsight and I can't think of a fluff beyond magical/works like truesight.

[Nerdynick]

Two other issues that might come up concerning blindsight:

1) Is blindsight sufficient for targeting spells?

2) How does blindsight interact with the blinded condition?

The second one came up because a fellow player at my table noted that some creatures with blindsight have immunity to the blinded condition. He argued that, consequently, a creature with blindsight suffers the penalties of being blinded, but can still pinpoint enemies.

[BiPolar]

Two other issues that might come up concerning blindsight:

1) Is blindsight sufficient for targeting spells?
I'd say yes, blindslight is a way to perceive, just not with your eyes.




2) How does blindsight interact with the blinded condition?

The second one came up because a fellow player at my table noted that some creatures with blindsight have immunity to the blinded condition. He argued that, consequently, a creature with blindsight suffers the penalties of being blinded, but can still pinpoint enemies.

This one is very interesting. I'd have expected any creature with blindsight to be immune to the Blind condition - as that condition only relates directly to seeing. However, given the disconnect, it does seem like Blindsight is another susceptible to Blind condition if the creature isn't immune.

[gfishfunk]

definitely like it...many instances you can figure out fluff for how they sense with blindsight, but do you see examples where it does end up like truesight or is there always a hidden weakness? For instance, Helmed Horrors have blindsight and I can't think of a fluff beyond magical/works like truesight.

It is an interesting question, but pose it as a GM creating an interesting encounter for a party:

Is the party a sneaky party? Are they going to look at ways to sneak by? In that case, give it an arc in the front of its head and have it obviously looking around. Have it respond to sound. I would not treat it like truesight, which goes through illusion, but I would have it ignore the invisible property.

Is the party a blast and kill party? The distinction largely doesn't matter then. It ignores invisibility. Queue in the party by having the first one's head on crooked and say it clearly knows where you are anyways. But only do that if blindsight ends up being important.


Two other issues that might come up concerning blindsight:

1) Is blindsight sufficient for targeting spells?

2) How does blindsight interact with the blinded condition?

The second one came up because a fellow player at my table noted that some creatures with blindsight have immunity to the blinded condition. He argued that, consequently, a creature with blindsight suffers the penalties of being blinded, but can still pinpoint enemies.

1. Yes.

2. Ignores the blinded condition, I would say, though the inconsistency is troubling.

I tell my players that all of my creatures are homebrewed. When I give them summons, they are also homebrewed. I generally do it to simplify things and make other things more interesting, but it also gets the meta-arguing off the table.

[RSP]

Just for the record, the OP is asking about RAW; they asked how it works. For reference:

Blindsight
A creature with blindsight can perceive its surroundings without relying on sight, within a specic radius.

I would say this definition ignores the Blinded condition in that they'd still have Blindsight as it specifically says it doesn't rely on sight so removing that creature's sight would not remove their Blindsight.

A creature with Blindsight and regular vision, such as a dragon or a bat, could be subject to the Blindness spell and lose their normal vision, but, per the RAW, would not suffer the Blinded condition. However, if that creature had Truesight and Blindsight, blinding it could stop its Truesight (up to DM as no ruling I'm aware of states the interaction between these two abilities).

Again, just stating the RAW for clarity, houserules are there for a reason.

[Nerdynick]

Just for the record, the OP is asking about RAW; they asked how it works. For reference:

Blindsight
A creature with blindsight can perceive its surroundings without relying on sight, within a specic radius.

I would say this definition ignores the Blinded condition in that they'd still have Blindsight as it specifically says it doesn't rely on sight so removing that creature's sight would not remove their Blindsight.

A creature with Blindsight and regular vision, such as a dragon or a bat, could be subject to the Blindness spell and lose their normal vision, but, per the RAW, would not suffer the Blinded condition. However, if that creature had Truesight and Blindsight, blinding it could stop its Truesight (up to DM as no ruling I'm aware of states the interaction between these two abilities).

Again, just stating the RAW for clarity, houserules are there for a reason.

Here's the thing, though. I'm not sure that you're interpretation is correct (though it is certainly how I would houserule it). Blindsight doesn't give any description of visual acuity other than saying it can detect the location of creatures. So, one could argue, being blinded still debilitates them because their blindsight isn't acute enough to properly land and defend from blows.

[BiPolar]

Definitely not RAW, but Perkins gave this recommendation (http://www.sageadvice.eu/2016/11/24/one-of-my-players-wants-to-play-a-blind-monk-with-blind-sight/) regarding a player who wants to play a Blind PC with Blindsight:

That shows there is a difference Blindsight and Blinded condition. And that Blindsight will work under Blinded.

But a Perkins ruling is still basically equivalent to a houserule.

Personally, I read blindsight as can "see" without need for "sight". Therefore Blinded, which affects sight, would not have an impact on someone with Blindsight. It kinda says it on the tin. Blind-Sight. Being put them under the BLinded condition is basically where they are now. But they ahve blindsight to get around it.

[RSP]

Nerdy,
The Blinded condition specifies its when you cannot see. As Blindsight allows one to perceive without sight, I'd go with that means the creature with Blindsight can function normally even while Blinded

[Asmotherion]

About Downsides:

If it uses Ecolocation (sound waves), wile it can see everything 3 dimensional, something 2 dimensional (like a drawing or script) would only appear as an empty piece of papper. Also a strong source of sound, such as a Thunder-Based Spell would interfere with this ability.

If it uses smell, strong odours (like garlic, pepper) might interfere with it's ability.

If it uses tremorsence (sencing through vibrations on the ground etc), it only knows "something" is at an apropriate distance and general shape, but not the precice person. Could potentially be fooled by droping something heavvy, or a spell like Earth Tremor or Mold Earth.

If it sences vibration and phermones in the air, (like snake's tongue), you can fool it by either a prestidigitation of the smell of an animal (see, prestidigitation does have an in-combat use after all :P ), or distract it with something strong in phermones (I leave that up to your interpretation).

I think that's about it.