What happens when a Shapechanged Dragon enters an Antimagic Field inside a narrow space? [duplicate]

A rather simple question: if an Ancient Dragon uses it’s Shapechange ability to transform into a medium-sized humanoid, and then has that Shapechange disabled/dispelled inside a narrow tunnel / small underground room, will they get crushed to death by their own size? I have plans on True Poly-ing my spellcaster PC into a Dragon, and i’m worried that a random dispel would instakill me when i go dungeon-delving in the Abyss or somewhere.

Can you Ready an attack with the trigger ‘enemy enters my reach’? If so, will you interrupt their movement on a hit?

Without using any feats, can a player with a reach weapon set that weapon to receive a ‘charge’ by the enemy, attacking them when they enter range? Or even a non-reach weapon? That is, can a player commit to using their attack action when an enemy crosses an arbitrary line with their movement? (Examples: Ready my glaive to attack when the orc gets 10′ away from me. Ready my shortbow to attack when the dragon enters 80′ from me. Ready my dagger in case the kobold comes adjacent.)

If this is possible, and the player’s attack hits, does it have any effect on the enemy’s remaining movement or other actions?

I think the answers are yes, and no, respectively.

Does Brace trigger when an enemy enters my echo’s reach?

The subclass feature Manifest Echo explicitly covers attacking from the Echo’s location when taking the Attack action or when taking a specific reaction:

  • When you take the Attack action on your turn, any attack you make with that action can originate from your space or the echo’s space. You make this choice for each attack.

  • When a creature that you can see within 5 feet of your echo moves at least 5 feet away from it, you can use your reaction to make an opportunity attack against that creature as if you were in the echo’s space.

My Echo Knight picked the fighting style Superior Technique with the Combat Maneuver Brace. This gives my fighter a new trigger for using a reaction:

When a creature you can see moves into the reach you have with the melee weapon you’re wielding, you can use your reaction to expend one superiority die and make one attack against the creature, using that weapon. […]

If I understand correctly, this would mean when an enemy enters my Echo’s reach, it does not trigger Brace, because it isn’t mentioned as possible scenario’s for attack from the Echo’s location. Is this interpretation correct?


Related:

  • Does an Echo Knight fighter's echo provoke an opportunity attack when it moves?
  • Does turning around count as moving for triggering Brace?

What happens if your body enters astral plane while under astral projection?

If a creature is under astral projection and their body is transported to astral plane, for instance because they got swallowed by the 2x bag of holding combo, what will happen?

Does the astral projection instantly end?
Does the astral projection get suspended until the body gets out the plane?
Does the creature get back to their original body in the astral plane when the spell ends?


Background:

Crawford tweets

In #DnD, the exceptional trumps the general. (No longer being a valid target trumps condition carryover.)

By entering astral plane, the creature would no longer be valid as the target of the spell (because astral projection specifically says so if the caster is on the astral plane), so I thought it will fail.

Does Aura of Courage end the frightened condition if a frightened ally enters its area of effect?

So I just made level 10 with my paladin and got the added feature “Aura of Courage.” I understand that currently I and anyone within 10 ft of me will be immune to the frightened condition. My question then:
If one of my allies is currently frightened and runs into my Aura, do they lose their frightened condition automatically? Or would they just pass through and keep running around?

I’m interested in RAW and what other DMs have ruled here.

What happens when the target of Ensnaring Strike enters the Ethereal Plane?

Ensnaring Strike states the following (abridged for brevity):

The next time you hit a creature with a weapon attack before this spell ends, a writhing mass of thorny vines appears at the point of impact, and the target must succeed on a Strength saving throw or be restrained by the magical vines until the spell ends. If the target succeeds on the save, the vines shrivel away.

Ensnaring Strike has a duration of Concentration, up to 1 minute.

What happens if the target of Ensnaring Strike enters the Ethereal Plane? They might accomplish this through methods such as the Etherealness spell.

Specifically:

  • Do the effects of the spell remain while they’re in the Ethereal Plane?
  • Can they pass through the vines that are holding them while in the Ethereal Plane?
  • Are the effects of the spell restored when they return from the Ethereal Plane?

Passwordless flow: What to do when user enters an invalid email when logging in

I’m planning to make my app passwordless and I’ve seen sites implement things differently when one puts in an email they haven’t actually used for an account on the site before when trying to login.

On Medium, if I put in a new email I’ll get the message “We just emailed a confirmation link to youremail@gmail.com. Click the link to complete your account set-up.”

This makes the signup process fast, but I’m not sure if this message is strong enough to make it clear to some users that this was a new email being used. This could frustrate users who had forgotten which email was used for their existing account and would now take the time to realize they’re using a new account before trying to login again with the right email. However, that scenario may not occur often enough that its worth designing the UX to prevent it.

Zeit does design things so if I don’t have an account and I put in a new email I’ll get the message “There is no ZEIT account associated with this email address. Continue with signup?” and I can click to signup.

This prevents one from realizing they used the wrong email, but it adds an extra step to signing up and I think it could confuse users who weren’t paying attention to the fact that they clicked login rather than signin.

What do you think is a better flow and why?

Can a character with the Polearm Master feat make an opportunity attack against an invisible creature that enters their reach?

The second benefit of the Polearm Master feat (PHB, p. 168) says:

While you are wielding a glaive, halberd, pike, quarterstaff, or spear, other creatures provoke an opportunity attack from you when they enter your reach.

The regular rules on opportunity attacks state:

You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.

Obviously, Polearm Master lets you use your reaction to make an opportunity attack when a creature enters your reach, in addition to the opportunity attack any character can make when a creature leaves their reach. However, does the opportunity attack from Polearm Master follow the same restriction on needing to see the creature, or can this attack be made even without seeing the creature that enters its reach?

If an invisible creature enters the reach of a character with the Polearm Master feat, can the character make an opportunity attack against that creature?