Is it possible for a swallowed caster to cast Fireball outside of a Giant Toad?

Question

I had a situation last week where my DM and I completely disagreed how the following situation should have been ruled:

I'm a Circle of the Moon druid wild-shaped into a Giant toad and I had swallowed a mage. The Swallow attack description says

"(...) The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the toad, (...)" (Giant toad, MM.)

But on the mage's turn he was able to cast Fireball at a point of his choice outside the Giant Toad, because Fireball's bright streak came from the Giant Toad's belly, exited the mouth, and struck a point outside the toad.

In broad terms, can a blinded caster choose a point outside of the Toad? And can a caster with total cover (in this case) target a point outside of the Giant Toad?

I've read the rules, especially regarding total cover and in fact it doesn't say anything about a person with total cover attacking someone who couldn't attack him because the cover. I would like to know if really it is possible for it to happen by RAW or RAI, because for me in this case total cover for those inside the Toad implies anyone outside it also has total cover, and vice versa.

Answer 1

The caster can choose any point in range, and try to cast a fireball there.

Whether there is a clear path, or not, is not relevant at this stage : the character is blinded, and can't know if there is one. A blinded character shouldn't be allowed to detect obstacles for free when targeting a point for an area of effect spell. Hence, he can choose any point in the spell's range.

It will most certainly backfire.

V2Blast appropriately reminded of the clear path to the target rule :

If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.

Obviously, there is an obstruction between you and any point outside the toad : the Giant Toad itself.
The fireball's point of origin will be located on the near side of the toad's belly, an the spell's full effect will remain inside it. Only the toad and the wizard are affected. Probably.

Though very unlikely, the DM might decide there's an occasional clear path somewhere :

• The swallow attack doesn't explicitly grant full cover to people outside. At least some air is passing, as it does not provoke suffocation.
• As Large the creature may be, a fully-geared adventurer isn't a light meal. Parts of it are probably still stuck in the throat of the toad.

He might call for luck here, and allow a (tiny) chance for the spell to resolve as expected by the caster. If not... Not only will the fireball's point of origin be located inside the toad (affecting again the toad and the wizard) - but it will also expand to a 20-foot sphere centered on the toad, as the fireball spreads around corners.

This might be effective - if the caster has some way to mitigate fire damage, and is surrounded by opponents.

Answer 2

You can't fire a fireball through a toad's mouth

The rules don't technically define 'swallowed', but in plain English, swallowed things are concealed by the relevant anatomy. Therefore, if a creature is swallowed by a toad, other creatures are completely concealed by that obstacle and therefore have toadal cover.

A target has total cover if it is completely concealed by an obstacle.

And the spellcasting rules say:

To target something, you must have a clear path to it, so it can't be behind total cover.

Therefore, if you try to target a point outside of the toad to be the center of the fireball, the center of the AOE will be inside the toad.

If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.

Answer 3

While I wouldn't allow it if I was your DM (though I'd allow the mage to quaff a fire resistance potion and cast a fireball inside your belly), I think one may be able to do that in the strictest, most perverse sense of the rules. Personally, I find such interpretations uncool, as they're not the kind of thing that enhance player experience. But I think it's arguably a legitimate interpretation.

My reasoning why it might be allowable is that the wording of the spell says "from your pointing finger to a point you choose within range". It doesn't say "target", it doesn't say "clear path", it doesn't say "...that you see", nothing of that kind. It doesn't say that the flash streaks in a straight path either, so it could very well go around corners. Or, up the esophagus and out the mouth.
All it basically says is: you point somewhere (and presumably have a concrete idea where you want "somewhere" to be, i.e. how far away), and that's it.
Since it doesn't say target, rules for targetting something don't apply in the strictest sense, so full cover doesn't apply. As long as you can point a finger, well, you can point a finger into the dark and unknown. Targets become targets if and only if they are within the blast.

Older editions of D&D explicitly said "determine the range (distance and height) at which the fireball is to burst". This makes it even more explicit that you don't target something or someone, but just choose a direction (by pointing) and a range (those old rules did however mention impact with a solid obstacle, but Q says the streak came out of the mouth, so that could arguably work).