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If I carry tiny creatures in my closed backpack, would they be immune to Fireball and other area of effect spells?

For example, is it possible to carry a horde of Tiny Servants (from the spell of the same name) in one's backpack, and have them stay in the backpack fully protected until they are needed?

Guillaume F.
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4 Answers4

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By RAW, yes

Area of effect spells like fireball do not target creatures, they target areas. So we turn to "Areas of Effect" in Chapter 10 of the Player's Handbook:

A spell's effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell's area. To block one of these imaginary lines, an obstruction must provide total cover. (PHB Chapter 10, pg 204)

A target with total cover can't be targeted directly by an attack or spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle. (PHB Chapter 9, pg 196)

A creature hidden in a backpack (assuming the flap is closed) is "completely concealed by an obstacle," granting it total cover. And per the above, if there is total cover between the center of the fireball spell and the creatures, those creatures are not affected by the spell.

If you're talking about fireball specifically, make sure to carry the backpack

From the description of fireball:

The fire spreads around corners. It ignites flammable objects in the area that aren't being worn or carried. (PHB Chapter 11, pg 242)

While your creatures will not take the initial fire damage, if the backpack is not being worn or carried, it will catch on fire, which is likely to damage them.

Lysanderoth
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  • @KorvinStarmast I wasn't asking the question as much as pointing out the major flaw in the reasoning. But I have not found anything else that refers to this, the question about the bedsheet is about concealment not cover. – John Apr 25 '21 at 13:15
  • Note it says " if no unblocked line extends to the location" not "to the creature" If the AOE hits the creature carrying the bag it should also hit the creature inside the bag, they are in the same location. If your interpretation is correct full body clothing should provide total cover. – John Apr 25 '21 at 17:34
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By RAW, a tiny creature can't be carried in a backpack to begin with.

The PHB is clear on the subject, on page 191:

Whether a creature is a friend or an enemy, you can’t willingly end your move in its space.

A tiny creature can't willingly end its turn in the backpack you are carrying, and you can't willingly end your turn carrying a backpack with a tiny creature in it.

Guillaume F.
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  • +1, however, they may be able to get 'around' this by having the tiny creature mount the larger one. But that then engages mounted combatant rules, which I don't think is what they want. – NotArch Apr 26 '21 at 13:55
  • @NautArch good point, although this depends on whether a player qualifies as a proper mount. Note that Tiny creatures still take up a 2 1/2 by 2 1/2 feet space (PHB p. 191). On a grid, up to 4 tiny creatures can fit in a 5 feet square. So even though a tiny creature could arguably "mount" a PC, only 1-4 can be carried at the same time. – Guillaume F. May 04 '21 at 14:39
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I had to deal with something similar with a pair of players. A gnome riding in a minotaur's backpack in my case.

I ruled that No it did not grant cover because a cloth bag is not an obstacle to an AOE and AOE affect spaces not creatures.

We know full cover can only be provided by obstacles.

A target with total cover can't be targeted directly by an attack or spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle. (PHB pg 196)

But we are never told what an qualifies as an obstacle, but we do know some things do not provide protection from AOE, total cover.

A target with total cover can't be targeted directly by an attack or spell, although some spells reach a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle. PHB p.196

SO total cover by itself is not enough something else must also be true. If we look at the rules for AOE we get a confounding answer and a hint

A spell's effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell's area. To block one of these imaginary lines, an obstruction must provide total cover. (PHB. pg 204)

So at first you might say total cover does or does not protect you depending on which passage you read. but notice that AOE's hit locations and if the creature is in the location simply blocking line of sight is not enough. After all the creatures in the bag are in the same location as the creature carrying it, so if the carrier is not protected the creatures in the bag are not as well.

Clothes and armor which also reasonably block line of sight a character but don't protect you from AOE because you are standing in the location hit by the spell. Wearing a ghost costume or full plate armor would not make you immune to fireball so hiding in a bag does not either.

You see some thing similar for the section deterring cover on a grid, line of sight and cover revolve around the entire space occupied by the creature not just the creature itself.

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I adjudicate it as: to protect from AOE, the thing between the source (point of origin) and target must provide a better barrier than armor or clothing, and must protect the entire square/hex/location you are in.

It would grant you concealment if you stay in the bag, and don't move around, it might even grant you cover depending on who you ask, but it does not protect you from AOE. Of course I could be wrong but without some better clarification that is what I ruled based on RAW, and not wanting players claiming standing behind a shower curtain protects them from dragons breath or the gust of wind spell.

John
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  • I can understand this, and I think a DM is well within their rights to rule whether something counts as an "obstacle," but this is not the RAW interpretation. A creature completely covered by a backpack has total cover, and you cannot draw straight lines between the spells origin and the creature's location without hitting that total cover. Your answer makes it sound like the RAW is ambiguous here depending on "which passage you read," when I don't really think it is. I don't know, I'm a new contributor -- am I being unreasonable here? – Lysanderoth Apr 25 '21 at 14:27
  • @Lysanderoth the ambiguity comes from the section about total cover, it specifically says AOE can still hit creatures who have total cover. The section on AOE's also says you need line of sight from the origin to the LOCATION of the creature, not to the creature. AOE hit spaces which contain creatures, not creatures. We see the same thing in section on flanking and cover on a grid, total cover must protect the entire space not just the visible creature. – John Apr 25 '21 at 17:28
  • Ah, I see. So if a space is obstructed from the AOE's origin, creatures within that space are unaffected. But if it's just a creature in a backpack in an unobstructed space, then they'd be hit. And as to when something counts as an obstruction, we defer to questions like Does hiding under a bedsheet provide Total Cover by RAW?. Well reasoned! I think you've convinced me. – Lysanderoth Apr 25 '21 at 20:27
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It might vary a bit depending on the spell, and there may be exceptions, but as a general rule I would say "yes", if they are entirely hidden inside it. If the backpack is open, or the tiny creature is peeking out of it, then "no" -- they could be affected. But most spells are defeated by total cover.

PhilB
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