D&D 5E Booming Blade seems a bit powerful

[Ganymede81]

But the second instance on the target won't deal damage, and it won't end, because "and the spell ends" is part of the spell's effect by my reading--it's something that a spell does between being placed on the target and the end of its duration

Ending the spell's duration with "the spell ends" is something that happens before the end of the spell's duration? The spell ending and no longer having an effect is an effect of the spell?

I tried. Play your game how you want; I'm not going to entertain this nonsense of yours any further.

 

[Arceliar]

Ending the spell's duration with "the spell ends" is something that happens before the end of the spell's duration? The spell ending and no longer having an effect is an effect of the spell?

I tried. Play your game how you want; I'm not going to entertain this nonsense of yours any further.

Fair enough. I think reasonable people would probably RAI that they don't stack and move on with life. I'm still concerned with figuring out what RAW says, even if nobody actually uses that interpretation, and I hadn't noticed this possible ambiguity in the rules until I read the Booming Blade thread.

Just to clarify (for anyone who is interested), when I say "duration", I mean Duration, as defined on PHB 203. In summary, it states that spells can be instantaneous or persist for some amount of time (which may be until dispelled or destroyed), and that the latter case may also require concentration. It does not specify durations of the form "1 round or until triggered", nor do such spells (Booming Blade, Death Ward, etc.) list such a constraint on the "Duration:" field of their spell descriptions--Booming Blade simply says "1 round", and I take it at its word. Instead, these spells list special circumstances under which something happens "and the spell ends". Since that's not included in the definition of Duration, and it falls under the part of the text which is used for the spell's effect, then when interpreting it RAW I'm inclined to conclude that the early ending aspects of such spells are part of their effects. Ending the effect does end the spell's duration, just the same as dispelling it would, but that's not the same as defining the spells duration with those ending conditions, due to the lack of such a rule (so far as I can tell) in 5e.

 

[Pathkeeper24601]

Fair enough. I think reasonable people would probably RAI that they don't stack and move on with life. I'm still concerned with figuring out what RAW says, even if nobody actually uses that interpretation, and I hadn't noticed this possible ambiguity in the rules until I read the Booming Blade thread.

Just to clarify (for anyone who is interested), when I say "duration", I mean Duration, as defined on PHB 203. In summary, it states that spells can be instantaneous or persist for some amount of time (which may be until dispelled or destroyed), and that the latter case may also require concentration. It does not specify durations of the form "1 round or until triggered", nor do such spells (Booming Blade, Death Ward, etc.) list such a constraint on the "Duration:" field of their spell descriptions--Booming Blade simply says "1 round", and I take it at its word. Instead, these spells list special circumstances under which something happens "and the spell ends". Since that's not included in the definition of Duration, and it falls under the part of the text which is used for the spell's effect, then when interpreting it RAW I'm inclined to conclude that the early ending aspects of such spells are part of their effects. Ending the effect does end the spell's duration, just the same as dispelling it would, but that's not the same as defining the spells duration with those ending conditions, due to the lack of such a rule (so far as I can tell) in 5e.

I think what you are missing is that both copies of the spell have the same trigger. Both copies of Booming Blade still have the same triggering mechanism. When the effected creature moves, both copies of the spell are triggered, but only the most powerful copy (say from lvl 3 vs. lvl 5 character) would apply its damage effect. Both are still triggered and both end.

The same is with Death Ward. Putting two copies on a player would be overkill. They both would trigger the first time the player goes to 0 hp or is hit with an instant death effect. The result would be the same regardless of how many Death Wards are triggered.

 

[Arceliar]

I think what you are missing is that both copies of the spell have the same trigger. Both copies of Booming Blade still have the same triggering mechanism. When the effected creature moves, both copies of the spell are triggered, but only the most powerful copy (say from lvl 3 vs. lvl 5 character) would apply its damage effect. Both are still triggered and both end.

The same is with Death Ward. Putting two copies on a player would be overkill. They both would trigger the first time the player goes to 0 hp or is hit with an instant death effect. The result would be the same regardless of how many Death Wards are triggered.

The triggering aspect is also part of the spell's effect, by my reading. While two instance of the same spell are affecting the same target, "instead" of combining, the most potent instance has an effect, and the second instance does not. It's still an ongoing spell, so it could e.g. be seen by detect magic, but it can't do anything while the more potent instance remains on the target. No triggering, no damage, and no ending itself early--those are all part of the spell's "effect" under my interpretation. To be clear, anything that the ongoing part of the spell does, compared to an imaginary blank spell with no effect, is what I'm calling the spell's effect, because that's the only thing I can think of that makes any sense to me (since the term was never precisely defined, they just gave an example for Bless). An imaginary blank spell with no effect cannot trigger on some condition, or end itself early, so those must be part of Booming Blade's effect under my interpretation. If there's anything in the rules to say that the trigger condition and early ending are not part of the spell's effect, then I don't see it.

Most spells with a trigger to end early do so "the first time" something happens, so it usually shouldn't matter if an impotent second instance hangs around and can't trigger, except as extra ongoing effects to see with detect magic, dispel, etc... there's probably some way for a DM to mess with players who keep doing that, or find some clever use for a particularly long or high level untriggerable spell, but otherwise I think it's just a weird quirk of the rules with little to no effect on anything. Booming Blade does not use "the first time" in the trigger condition, and Death Ward only uses it in one of its possible trigger conditions, so in those cases the distinction becomes important.

 

[Arial Black]

The triggering aspect is also part of the spell's effect, by my reading. While two instance of the same spell are affecting the same target, "instead" of combining, the most potent instance has an effect, and the second instance does not. It's still an ongoing spell, so it could e.g. be seen by detect magic, but it can't do anything while the more potent instance remains on the target. No triggering, no damage, and no ending itself early--those are all part of the spell's "effect" under my interpretation. To be clear, anything that the ongoing part of the spell does, compared to an imaginary blank spell with no effect, is what I'm calling the spell's effect, because that's the only thing I can think of that makes any sense to me (since the term was never precisely defined, they just gave an example for Bless). An imaginary blank spell with no effect cannot trigger on some condition, or end itself early, so those must be part of Booming Blade's effect under my interpretation. If there's anything in the rules to say that the trigger condition and early ending are not part of the spell's effect, then I don't see it.

Most spells with a trigger to end early do so "the first time" something happens, so it usually shouldn't matter if an impotent second instance hangs around and can't trigger, except as extra ongoing effects to see with detect magic, dispel, etc... there's probably some way for a DM to mess with players who keep doing that, or find some clever use for a particularly long or high level untriggerable spell, but otherwise I think it's just a weird quirk of the rules with little to no effect on anything. Booming Blade does not use "the first time" in the trigger condition, and Death Ward only uses it in one of its possible trigger conditions, so in those cases the distinction becomes important.

Cogently and convincingly argued.

TL;DR, both the trigger for the damage and the spell ending before the duration expires are as much 'effects' of the spell as the damage it does. If the damage of the second spell is suppressed while the first still exists, then the entirety of the second spell's effects, including 'trigger' and 'ends early', are equally suppressed. Both the 'trigger' and 'ends early' only exist as part of the spell's effect, re: PHB p202, Casting A Spell, which clearly states:-

"Each spell description in chapter 11 begins with a block of information, including the spell’s name, level, school of magic, casting time, range, components, and duration. The rest of a spell entry describes the spell’s effect."

Since the 'trigger' and 'ends early' clauses only exist in the 'spell effect' portion of the spell's description, then they must be part of the spell's effect. QED.

 

[Ovinomancer]

Cogently and convincingly argued.

TL;DR, both the trigger for the damage and the spell ending before the duration expires are as much 'effects' of the spell as the damage it does. If the damage of the second spell is suppressed while the first still exists, then the entirety of the second spell's effects, including 'trigger' and 'ends early', are equally suppressed. Both the 'trigger' and 'ends early' only exist as part of the spell's effect, re: PHB p202, Casting A Spell, which clearly states:-

"Each spell description in chapter 11 begins with a block of information, including the spell’s name, level, school of magic, casting time, range, components, and duration. The rest of a spell entry describes the spell’s effect."

Since the 'trigger' and 'ends early' clauses only exist in the 'spell effect' portion of the spell's description, then they must be part of the spell's effect. QED.

But that doesn't mean that one spell 'goes to sleep' and doesn't check it's triggers, only that the most effective result is applied when triggered. If there are two castings of booming blade, for instance, only the most potent effect is applied, but how do the spells tell which is most potent before they are triggered? How can the suppressed version know that they other is the most potent? Simply, they cannot. The effects are in existence at the same time but only the most powerful result is applied. One spell doesn't sleep and wait for the other to finish. Instead, both spells MUST trigger and MUST check their damage in order for the most potent to be applied, at which point the end of spell mechanism has already be achieved and both spells end. Further, you introduce the issue of how do you resolve the damage for the second booming blade? Do you reroll when it's applied, or take the roll to check against the first application, which causes issues of how did that happen, since it hasn't resolve. If you re-roll, is the first damage application a hard ceiling, or is this a new resolution and the old one was just for that trigger?

Both spells are active, both spells trigger at the same time, but only the most potent damage is applied, then both spells end. One spell cannot determine that the other will be more powerful and go to sleep until the first resolved. Otherwise, the 'most potent effect' rule has almost no cases where it applies, as you can use the logic of the sleeping spell from almost every case it would.

 

[Arial Black]

But that doesn't mean that one spell 'goes to sleep' and doesn't check it's triggers, only that the most effective result is applied when triggered. If there are two castings of booming blade, for instance, only the most potent effect is applied, but how do the spells tell which is most potent before they are triggered? How can the suppressed version know that they other is the most potent? Simply, they cannot. The effects are in existence at the same time but only the most powerful result is applied. One spell doesn't sleep and wait for the other to finish. Instead, both spells MUST trigger and MUST check their damage in order for the most potent to be applied, at which point the end of spell mechanism has already be achieved and both spells end. Further, you introduce the issue of how do you resolve the damage for the second booming blade? Do you reroll when it's applied, or take the roll to check against the first application, which causes issues of how did that happen, since it hasn't resolve. If you re-roll, is the first damage application a hard ceiling, or is this a new resolution and the old one was just for that trigger?

Both spells are active, both spells trigger at the same time, but only the most potent damage is applied, then both spells end. One spell cannot determine that the other will be more powerful and go to sleep until the first resolved. Otherwise, the 'most potent effect' rule has almost no cases where it applies, as you can use the logic of the sleeping spell from almost every case it would.

If we follow that logic, then both spells have their damage rolled and a total amount of damage for each spell is generated. It's just that we only apply the largest of these two totals.

It is do-able, but is this what 5E has us do? Specifically, do we note that the two spells are the same, choose the one that is the highest level, then roll only once and apply that? Or, as you suggest, we roll both sets of damage, but only apply the highest result?

Let's see what 'Combining Magical Effects' on PHB p206 says:-

"For example, if two clerics cast bless on the same target, that character gains the spell’s benefit only once; he or she doesn’t get to roll two bonus dice".

He does not get to roll the bonus d4 twice and add them together; we all agree on that.

He also does not get to roll the bonus d4 twice and apply the highest result! He does not get to roll two bonus dice at all! Not according to the quote.

That means that the second spell simply does not even trigger, nor does it have any effect. If it did trigger then we would indeed need to roll a second bonus d4 for bless, but only apply the highest. Since we know for a fact that the second d4 was never rolled, it follows that the spell did not even trigger. The only thing preventing it from triggering is the existence of the first spell.

That results in the conclusion that the second spell, while not being consciously 'aware' as such, is prevented from having its effect by the existence of the already in-place effect of the first spell.

Since the 'trigger' and the 'end early' definitely are part of the effect (of booming blade), then they, as part of that effect, are prevented from taking effect at all by the presence of the effect of the first spell.

 

[Sorcerers Apprentice]

If we follow that logic, then both spells have their damage rolled and a total amount of damage for each spell is generated. It's just that we only apply the largest of these two totals.

It is do-able, but is this what 5E has us do? Specifically, do we note that the two spells are the same, choose the one that is the highest level, then roll only once and apply that? Or, as you suggest, we roll both sets of damage, but only apply the highest result?

Let's see what 'Combining Magical Effects' on PHB p206 says:-

"For example, if two clerics cast bless on the same target, that character gains the spell’s benefit only once; he or she doesn’t get to roll two bonus dice".

He does not get to roll the bonus d4 twice and add them together; we all agree on that.

He also does not get to roll the bonus d4 twice and apply the highest result! He does not get to roll two bonus dice at all! Not according to the quote.

That means that the second spell simply does not even trigger, nor does it have any effect. If it did trigger then we would indeed need to roll a second bonus d4 for bless, but only apply the highest. Since we know for a fact that the second d4 was never rolled, it follows that the spell did not even trigger. The only thing preventing it from triggering is the existence of the first spell.

That results in the conclusion that the second spell, while not being consciously 'aware' as such, is prevented from having its effect by the existence of the already in-place effect of the first spell.

Since the 'trigger' and the 'end early' definitely are part of the effect (of booming blade), then they, as part of that effect, are prevented from taking effect at all by the presence of the effect of the first spell.

If a target is subject to two instances of Booming Blade that are equally potent, how do you decide which one triggers first?

 

[KarinsDad]

Frankly, I wish that more spells offered this type of choice. I think it makes things more interesting and dynamic.

One would think so reading the cantrip.

But in actual game play, it almost never does anything. Or at least IME.


We have a 10th level Arcana Domain Cleric with both Booming Blade and Green-Flame Blade and Shillelagh. The PC is specifically designed to take advantage of these two cantrips.

In nearly 10 full levels of play, Booming Blade might have done it's additional damage 6 or 8 times. A few times, the PC Wizard has dropped a Bonfire on the same foe and it has to take extra damage from one cantrip, or the other. But usually the Wizard is too busy doing something more worthwhile. And the Cleric even typically uses Booming Blade more often than Green-Flame Blade since we are playing Storm King's Thunder (a modified version of the quest so that the PCs have to go to every single giant lair as part of the quest), so we fight a lot of larger creatures, giants, etc. and they just don't stack themselves together like a bunch of small or medium foes would. Even with the situational incentive to use Booming Blade when not casting a spell, it just rarely gets its bonus damage.

It might "control" the foes to some minor extent, but since the Cleric has Spiritual Guardians up nearly every non-trivial encounter, foes want to stay put anyway (and the Cleric often has a huge bullseye on her back). The control is often redundant to the control of Spiritual Guardians (i.e. if a foe moves away from Spiritual Guardians, there are often few things that prevent the Cleric from just following that foe, so many foes have an incentive to just stay put and kill the Cleric or disrupt the Concentration of the Cleric). One would think that Spiritual Guardians would incentivize NPCs to flee, but instead it often (regardless of DM) incentivizes them to attack the Cleric (at least the semi-intelligent foes).


With a different build and different party makeup and different set of DMs/adventures (we have 3 rotating DMs who run the game for 3 to 6 months each depending on what else is going on in life), it could have more utility. But it doesn't seem to do that much in our group.

 

[KarinsDad]

If a target is subject to two instances of Booming Blade that are equally potent, how do you decide which one triggers first?

The one that hit the target first. It's the "first" spell. That's the simplest way to adjudicate it.

This does beg the question about Booming Blade used by a PC that does more damage with it (e.g. like an Arcana Domain Cleric who boosts cantrip damage). In that case, I would rule that the cantrip that does more average damage is the more potent cantrip.