The situation I have in mind is the following:

An epic battle ensues between a Young Green Dragon (caster variant) and a Purple Worm. The Purple Worm swallows the dragon; meanwhile, the dragon has blindsight and can cast Command.

Command is a spell that requires you to see the target. However, the dragon is Blinded (so it can't see) while swallowed. It has blindsight out to 30 ft, though, so it can perceive its surroundings without relying on sight.

Can the Young Green Dragon use the Command spell to have the Purple Worm retch it out?

The general question is: does the interaction of the Blinded condition with blindsight still prevent the caster from using spells that require them to see the target?

There is another question which asks if creatures with blindsight can be affected by the Blinded condition. The answer is yes, and we begin this question with the fact in mind that the caster is both Blinded and has blindsight.

  • \$\begingroup\$ Meta here \$\endgroup\$
    – user27327
    Commented May 7, 2017 at 12:13

4 Answers 4


A Blinded, Blindsight-possessing caster can still cast its sight-dependant spells

The Blinded condition is defined as;

A blinded creature can't see and automatically fails any ability check that requires sight. attack rolls against the creature have advantage and the creature's attacks have disadvantage

while blindsight is written as;

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

A creature with blindsight does not require or rely on sight within the specified radius so the first aspect of the blinded condition is nullified within the region of blindsight. the second aspect however is not directly countered.

RAW a creature with blindsight can still do anything that requires sight within that range including casting spells, but would have disadvantage on attack rolls due to the blinded condition.

creatures that have no eyes such as oozes are already immune to the blinded condition so there shouldn't be any issues with the inherent logic with them. but a creature with blindsight that is blinded (such as the aforementioned dragon) would still be worse off than one that is not blinded.

  • 2
    \$\begingroup\$ But how does that interfere with the actual casting of command? It requires no attack rolls, so it seems like you are saying that it can, just not outright. \$\endgroup\$ Commented May 8, 2017 at 20:20
  • \$\begingroup\$ can cast it as long as the creature is within the blindsight radius. \$\endgroup\$
    – Daniel
    Commented May 13, 2017 at 4:31
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    \$\begingroup\$ @Daniel I edited that into your answer, feel free to rollback, but you should include something to that effect. \$\endgroup\$ Commented May 13, 2017 at 16:51
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    \$\begingroup\$ Ummm ... think about an invisible small innocent gnome trapped, and totally and unfairly restrained by two muscular guards grabbing her. An evil human prophet approach her and (taking his time) he observe her: hearing his moans, grabbing her with one hand, even noticing the small footprints she was creating at that moment. He is perceiving the gnome, maybe in much more ways than a creature with blindsight!. It would be safe to say that, since the prophet is not seeing the gnome, he can't cast a Command spell over her? Would not a creature with blindsigth have the same problem? \$\endgroup\$
    – Abby
    Commented Jun 13, 2017 at 18:30

Yes to the specific scenario; Maybe for other scenarios.

I think the correct answer on this can be very situation specific. The answer, as it relates to whether a green dragon in the belly of a purple worm can Command it to vomit, is yes. Although the dragon is blinded by virtue of being swallowed, it can still see the target of the spell because of it's blindsight ability. Even if it can't see the worm's head or external body (which aren't a requirement for casting), the lining of the stomach is right adjacent to it in this scenario and ripe for targeting.

However, Jeremy Crawford's tweet does create situations wherein a blinded creature with blindsight could not target a creature because that creature is specifically hiding:

Blindsight lets you spot an invisible creature in range, but that creature can still try to hide behind something with Stealth.

By my reading of this, it wouldn't matter if the creature with blindsight were blinded or not. The blindsight ability would permit them to attempt a perception check against the opposed stealth check within their range. Were they not blinded, they could attempt the perception check beyond their blindsight radius.

I think the common misperception is that blindsight is having perfect vision with the stated radius. But that is not the case nor the intent. Instead, blindsight simply allows you to perceive within the stated radius to the extent that your perception check permits. If a creature is not attempting to hide within that radius, then you'd perceive it as one normally would with regular senses. If something is trying to hide, then you can attempt to find them regardless of effects that might blind you, effectively or otherwise (i.e. being blinded, fog cloud, magical darkness, etc.)

So if the blinded dragon were to succeed on a perception check to spot a rogue hiding within their blindsight radius then yes, they could target them with a spell. Otherwise, they could not because they aren't sure where to target the spell.

  • 1
    \$\begingroup\$ If anyone's having trouble imagining someone hidden from blindsight, here are some examples. A) Hiding from echolocation behind an obstacle that reflects the sound waves, b) hiding from a creature's sense of smell by moving downwind or near smelly distractions, c) disguising the tremors on the ground by floating/flying if you can or moving very carefully if you can't, etc. Often the creature's stat block will give you hints about the nature of their blindsight, eg if deafened condition interferes with it. \$\endgroup\$ Commented Oct 17, 2019 at 14:54

A blinded caster with Blindsight cannot use spells that requires it to see

Blindsight states (PHB p183):

A creature with blindsight can perceive its surroundings without relying on sight, within a specific radius. Creatures without eyes, such as oozes, and creatures with echolocation or heightened senses, such as bats and true dragons, have this sense.

Blindsight uses some creature-specific sense(s) other than sight to perceive. In other words, Blindsight has no effect whatsoever on a creature's ability to see.

A caster with the blinded condition and the Blindsight ability can perceive its surroundings, but cannot see. Hence, that caster cannot successfully cast spells that require it to see.

  • \$\begingroup\$ I think you could make your point more clear by including text from Command and highlighting how the requirement is "that you can see" rather than "that you can perceive" \$\endgroup\$
    – user60913
    Commented Sep 29, 2020 at 22:14


Blindsight is defined for us in the PHB section on Vision and Light:

A creature with blindsight can perceive its surroundings without relying on sight, within a specific radius. Creatures without eyes, such as oozes, and creatures with echolocation or heightened senses, such as bats and true dragons, have this sense.

Given only this definition of 'perceiving without sight', it certainly appears prima facie that one should not be able to cast spells that rely on sight if one has access to only blindsight.

However, a ruling in Sage Advice Compendium shows that RAI is the contrary:

Can a blinded creature make an opportunity attack? An opportunity attack is triggered by “a hostile creature you can see” (PH, 195). If you can’t see an enemy, you can’t make an opportunity attack against it. Creatures with blindsight are an exception to this rule, because that ability lets those creatures “see” within a certain radius.

Apparently blindsight is supposed to be treated as sight for its interactions with other sight-based rules, and thus can be used to allow the casting of spells that rely on sight. As Darth Pseudonym says, "Blindsight counts as seeing, even though it isn't."

As a final note, 'retch' (or as the purple worm description puts it, 'regurgitate') is not 'on-list' for uses of the Command spell, and it is not even clear that doing so is something under the voluntary control of the worm. As such, command says:

You might issue a command other than one described here. If you do so, the DM determines how the target behaves. If the target can't follow your command, the spell ends.

You might wish to read Could the spell Command make a target drop concentration? as you reflect on this.


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