Booming blade - how does it crit, and is this legit?

[Ancalagon]

Hello

Two questions about this spell.

First, is the following "mini combo" legitimate?

With the feat warcaster, you can cast a spell as a reaction instead of attacking as an attack of opportunity. So when an attack of opportunity is triggered by someone moving out of your threatened square, you do this, and boom they take the extra damage for moving automatically. Is this right?


Second, if the above happens, what gets doubled on a critical hit?

Normally, the "damage if you move" doesn't increased because the movement is not happening at the same time as the attack. But in this case, it does. So does this damage get doubled?


Bonus question, aka "the bastard combo".

Booming blade clearly states " the target willingly moves". So you can't booming blade someone then shove them or something to trigger the "if move" damage. The target has to move on their own accord.

BUT

What if you make the target move not by force but by some mental compulsion? Suggestion, or fear? You essentially "hack their will" - they are now willing to move away, and do so on their own...

 

[LudicSavant]

I would rule that the extra damage from the melee attack crits. The damage from moving is a separate effect from the hit itself, and therefore would not be multiplied.

 

[Paul Farquhar]

The person hit with the Booming Blade could choose to stop moving the instant they are hit, thus avoiding the sonic damage. Ergo, Sonic damage is separate from the attack damage and doesn't get to crit.

 

[Caliban]

The person hit with the Booming Blade could choose to stop moving the instant they are hit, thus avoiding the sonic damage. Ergo, Sonic damage is separate from the attack damage and doesn't get to crit.

I agree.

 

[Caliban]

BUT

What if you make the target move not by force but by some mental compulsion? Suggestion, or fear? You essentially "hack their will" - they are now willing to move away, and do so on their own...

My opinion: this should cause it to trigger (because they are moving under their own power, rather than being pushed/pulled).

Sage Advice/Jeremy Crawford says it won't, for what it's worth. https://www.sageadvice.eu/2016/04/0...nt-whispers-be-willing-or-unwilling-movement/

To me, this ruling would mean that the booming blade spell is sentient and can decide if you are moving willingly or not. So it actually summons a small thunder elemental that sits there waiting to smack you if you move, but it will give you a pass if you look really scared or are ordered to move by someone else who has a friend of yours hostage and you are "unwilling but following orders".

 

[UngeheuerLich]

My take is that the booming energy manifests in the brain. So it dors not have to be sentient but it is just zapping you if your brain sends signals to your muscles not a spell that overrides your brain function.

 

[Caliban]

My take is that the booming energy manifests in the brain. So it dors not have to be sentient but it is just zapping you if your brain sends signals to your muscles not a spell that overrides your brain function.

[video=youtube;pjnZO5ZgWE8]https://www.youtube.com/watch?v=pjnZO5ZgWE8[/video]

 

[Ancalagon]

The person hit with the Booming Blade could choose to stop moving the instant they are hit, thus avoiding the sonic damage. Ergo, Sonic damage is separate from the attack damage and doesn't get to crit.

I don't know about that - and by that I mean I'm unsure. The issue is... how does the spell work anyway? Does the person affected by it even know that they will take damage if they move? How do they know? Is it like [MENTION=284]Caliban[/MENTION] says and there is a small elemental looking at you tapping its foot angrily?

 

[jaelis]

Bonus question, aka "the bastard combo".

Booming blade clearly states " the target willingly moves". So you can't booming blade someone then shove them or something to trigger the "if move" damage. The target has to move on their own accord.

BUT

What if you make the target move not by force but by some mental compulsion? Suggestion, or fear? You essentially "hack their will" - they are now willing to move away, and do so on their own...

Rules aren't very clear on this. I would play that if the target spends its own movement to move, then BB would trigger.

But the two cases you mention have their own issues. Suggestion fails if you tell the target to do something obviously harmful; triggering BB would seems to count. Fear makes a creature move away from you by the safest available route. If there is nowhere to move, they don't have to. Well that is ambiguous, what if there is nowhere safe to move? That's a ambiguity for fear, not just booming blade.

 

[Paul Farquhar]

I don't know about that - and by that I mean I'm unsure. The issue is... how does the spell work anyway? Does the person affected by it even know that they will take damage if they move? How do they know? Is it like [MENTION=284]Caliban[/MENTION] says and there is a small elemental looking at you tapping its foot angrily?

The spell description implies a visual effect.

But that's irrelevant. It doesn't matter why the target stops - they might have decided they have gone far enough, or run out of movement, or backed to the edge of a cliff. The point is, the opportunity attack is triggered by movement that occurs before the attack. The Boom effect is triggered by movement that occurs AFTER the attack hits. Ergo they are not simultaneous. Ergo the Boom effect cannot crit.


If you are playing on a grid: the target moves a square and triggers the opportunity attack, which hits with booming blade. If, and only if, they then move another square do they take the spell damage.