A creature without darkvision cannot see in non-magical darkness, the wording concerning darkvision is simply an effort to make it clear that darkvision is defeated by this spell.  Note the second part, a nonmagical light can't illuminate it.  The wording of this spell description could and should be better; it should explicitly state that it causes the heavily obscured condition.

A darkness spell creates a sphere of magical darkness.  Unlike natural darkness, light doesn't shine in it and doesn't pass through it.  A campfire on the other side of the area effect of a darkness spell cannot been seen through it, though the flickering orange light of the campfire may be seen reflecting off any trees or walls or whatever else may be in the environment but outside the area of effect.

Everything inside the sphere will be heavily obscured to outside observers, and anyone inside the sphere is effectively blind unless they possess the specific ability to see in magical darkness, which is explicitly listed for those few rare creatures who can.  Non magical light sources like the campfire that are inside the sphere do not produce light at all while inside the area of the darkness spell.

Will a darkness spell cast on a pebble or other small object placed inside a bullseye lantern cast a 15' cone of magical darkness? 

Or, since the spell says the darkness spreads around corners, will this still result in the normal 15' sphere?  Presumably a hooded lantern should work to cover and uncover magical darkness, though a small box or pouch should work just as well, correct?

Quote from Cynnewulf >>

A creature without darkvision cannot see in non-magical darkness, the wording concerning darkvision is simply an effort to make it clear that darkvision is defeated by this spell.  Note the second part, a nonmagical light can't illuminate it.  The wording of this spell description could and should be better; it should explicitly state that it causes the heavily obscured condition.

A darkness spell creates a sphere of magical darkness.  Unlike natural darkness, light doesn't shine in it and doesn't pass through it.  A campfire on the other side of the area effect of a darkness spell cannot been seen through it, though the flickering orange light of the campfire may be seen reflecting off any trees or walls or whatever else may be in the environment but outside the area of effect.

Everything inside the sphere will be heavily obscured to outside observers, and anyone inside the sphere is effectively blind unless they possess the specific ability to see in magical darkness, which is explicitly listed for those few rare creatures who can.  Non magical light sources like the campfire that are inside the sphere do not produce light at all while inside the area of the darkness spell.

Quote from Cynnewulf >>

Will a darkness spell cast on a pebble or other small object placed inside a bullseye lantern cast a 15' cone of magical darkness? 

Or, since the spell says the darkness spreads around corners, will this still result in the normal 15' sphere?  Presumably a hooded lantern should work to cover and uncover magical darkness, though a small box or pouch should work just as well, correct?

I actually saw this being played out not too long ago but and it's complete and udder darkness no one can see through it, darkvision or otherwise. And no light can illuminate it either, magical or non-magical.

I agree that stating it heavily obscured objects within the radius would be helpful. That said, darkness is specifically called out in the Vision and Light section as both being heavily obscured for vision and magical darkness is specifically called out in the Darkness section.

Would superior dark vision of the drow be able to see through this?

So I’m just trying to confirm something.

”If the point you choose is an object you are holding or one the isn’t being worn or carried, the darkness eminates from the object and moves with it.”

Is it just me or would this make more sense for this sentance to say “IS being worn”. From the context it seems as though that’s what it’s trying to say, or is it trying to say you can’t cast it in an object being worn?

Quote from Wulvrum >>

I actually saw this being played out not too long ago but and it's complete and udder darkness no one can see through it, darkvision or otherwise. And no light can illuminate it either, magical or non-magical.

 Magical light works. Only nonmagical light doesn't.

Quote from Nighthawk909 >>

Would superior dark vision of the drow be able to see through this?

The Superior Darkvision trait just increases darkvision range. It's still darkvision.

Quote from Icebringer13 >>

So I’m just trying to confirm something.

”If the point you choose is an object you are holding or one the isn’t being worn or carried, the darkness eminates from the object and moves with it.”

Is it just me or would this make more sense for this sentance to say “IS being worn”. From the context it seems as though that’s what it’s trying to say, or is it trying to say you can’t cast it in an object being worn?

You can't cast it on an object that's being worn or carried by someone else.

But you can cast it on something worn or carried by yourself?

Yep! In the description. The magical darkness emanates from the object you are holding. If you have the warlock invocation of "devil's sight" and cast darkness on your pact weapon if you are pact of the blade, you can go to town on any creatures within 15 ft of you, as they'll be effectively blind unless they have truesight or some other sense, and your pact weapon is the source of the darkness, moving with you. Can make for a wicked combination!

Anything short of blindsight

Would a light cantrip counteract this?

If any of this spell's area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.

no, a light cantrip would be dispelled since it's an area of light created by a spell of 2nd level or lower.

Would the caster be able to see normally, or are they also affected by the darkness?

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Don't cast it on a dragon. If you do you are just begging for a tpk and death stares from the rest of the table.

Those are some intense mental acrobatics XD

I just want to make sure, but the caster is also affected by the blindness. Just cause you casted it doesn’t mean you can see in it correct?

Can my "Find Steed" Warhorse still manoeuvre fully when I have devils sight / darkness combo up?  It has no devils sight,  but I communicate with it by thought alone, so can I still ride it unhindered I wonder?