D&D 5E ToA: Dispel Magic in the Tomb

(posted before seeing Robus' reply)

The Rules said:

Any character can attempt an Intelligence (Arcana) check to detect or disarm a magic trap, in addition to any other checks noted in the trap’s description. The DCs are the same regardless of the check used. In addition, Dispel Magic has a chance of disabling most magic traps. A magic trap’s description provides the DC for the ability check made when you use Dispel Magic.

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This seems pretty clear cut. No houserule suggestions necessary.

I'm guessing is the concern for players simply casting Dispel Magic on any suspicious door or similar.

But if so, I am struggling to see the harm. A 3rd level slot is not a trivial expenditure. And if they don't upcast it, chances are the dispelling won't be automatic, and therefore there is a significant risk the spell is wasted.

Casting Dispel Magic on every possible trap is a great way to arrive at the next combat depleted of spells, and therefore should be encouraged by evil DMs!

The real issue, at least for me, is that each party is likely to contain at least one character for which spotting and disabling traps is very easy.

The only traps in Tomb of Annihilation I had any luck with (defined as "having a non-negligible impact on party resources") was those that were hidden and even undetectable. I wish they ever spent 3rd level slots on traps...!

robus said:

Well I was making these comments over a year ago But I remember there was at least a couple of traps that were susceptible to dispel magic (which made me go "wuh?") and thus the trap was neutralized.

I'll have a reskim through that section of the book this evening and pull out a couple of examples, it was quite plain in my reading.

Also I've not run this adventure (we're still slogging through my OotA reboot) so this was all theoretical.

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Yeah I noticed (that this is a necro), and thinking you wouldn't maybe reply, I went ahead and had a theoretical discussion (or monologue)

To me it just made no sense that Acererak would leave some traps vulnerable to dispel magic. Magic is his bread and butter and he had the time to design this tomb to his exacting (I imagine) standards.

So it's not about the rules, it's about the inherent logic of the tomb and its designer and how that logic is exposed to the PCs. Some traps allow dispel magic others don't for no good explicable reason (if you're imagining the tomb has been created by Acererak).

robus said:

Some traps allow dispel magic others don't for no good explicable reason (if you're imagining the tomb has been created by Acererak).

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I think I have a guess as to what the cause of your... apprehension... is.

Dispel magic is mentioned on occasion in Chapter 5: Tomb of the Nine Gods.

The reason for this is not that every other trap can't be dispelled.

The reason is that the text is discussing a "non-trap trap" - that is, something the adventurers might want to dispel without it being a "formal" trap. So what the text is doing is merely to add dispel magic to the prospective tomb robbers' arsenal for these features.

That magic traps can be dispelled is a core rule from the DMG, and not something overruled or even discussed by the chapter. Dispel magic is not on the page 128 list of modified spells, for instance.

Several traps and other hazards are protected by Acecerak. But the chief defense is... not triggering the heroes' suspicion. Or misdirecting it. That is, if they cast dispel magic it might well work, but in many cases they won't because they have no reason to - and it is too expensive to spend a third level slot every time something seems off (as a DM it is our job to make sure that's the case). Or they have reason but cast it in the wrong place, and so on...

Do note detect magic doesn't generally reveal magic traps. Each such trap will have to present any details on an individual basis, like with the fire-breathing statue (the DMG example magic trap).

I think that if Acecerak would hear your concerns about dispel magic he would (scornfully reply: the defense against dispel magic is to have more traps

That is - while I see your logic "the traps of the master of traps can't be puny dispellable traps" I do not see it as something that needs a solution as drastic as making the traps immune to dispel magic.

At most I would suggest you identify your favorite traps - the ones you feel make for a more memorable experience if they actually go off - and then decide Acecerak has cast them at spell level 9. This makes them close to functionally immune - either the heroes cast dispel magic using a level 9 slot (which they don't have) or they need to make a spellcasting roll with DC 19 (which given a +5 casting modifier should be a 35% chance tops).

But I would keep this to a minimum, and I would make sure detect magic makes it clear strong magic is used (= that dispel magic is likely to fail).

Then I would allow all the other (magic) traps to be automatically dispelled when and if dispel magic is used (unless the module says otherwise, of course). I really see no way this will happen very often, so I see no reason to hold back the payout for when the party does use this option. In my run through the module - all of it - I can't remember them using dispel magic more than half a dozen times.

CapnZapp said:

I think that if Acecerak would hear your concerns about dispel magic he would (scornfully reply: the defense against dispel magic is to have more traps

That is - while I see your logic "the traps of the master of traps can't be puny dispellable traps" I do not see it as something that needs a solution as drastic as making the traps immune to dispel magic.

At most I would suggest you identify your favorite traps - the ones you feel make for a more memorable experience if they actually go off - and then decide Acecerak has cast them at spell level 9. This makes them close to functionally immune - either the heroes cast dispel magic using a level 9 slot (which they don't have) or they need to make a spellcasting roll with DC 19 (which given a +5 casting modifier should be a 35% chance tops).

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I actually like the idea that was demonstrated in one of the traps that allowed dispel magic (and I noted last year). It actually made the challenge harder. That seems like a nice twist that Acererak would enjoy . So if I were to run it I would try to figure out how to pull that off more often.

Consider also a Glyph of Warding set up as a spell glyph set up to counterspell a dispel magic.