Will side 1 of a Cube of Force, which blocks gasses, block a breath attacks? The flames of a dragon spawn from its breath and therefore are based on a gas. Would the first side of the Cube of Force stop the attack? This would also apply to any type of elemental breath attacks of dragons, or even dragonborn racials.


2 Answers 2


No (mostly)

Breath attacks that aren't based on gas or wind would be unaffected. A red dragon's flaming breath attack is not harmful because it's windy or gassy, it's harmful because it's fire. Similarly a blue dragon's lightning “breath” and a black dragon's acid breath are harmful because they spit streams of lightning and acid, not because they're blowing on you.

Breath weapons based on gas would be affected just fine though: a gorgon's petrifying breath or a green dragon's chlorine gas breath are both harmful gasses, which the Cube of Force could block. You can tell because their descriptions call them “poison gas” and “petrifying gas”, respectively. Similarly, the Cube would keep you safe from an air elemental entirely because it is made of wind.

If you want to block non-gasses, use the other faces of the Cube — that's what they're there for. A gout of acid would be blocked by face 2, and something like a red dragon's fire would be blocked by face 5. Sure, they cost more charges, but the Cube is self-charging, so there's no need to lawyer-up (or worse, suddenly assert that D&D is science fiction and science-up; you do not want to dive down the science rabbit hole when dragons are involved, nevermind the lesser but still Gordian metaphysical knots you'd tie yourself into trying to define the distinctions made by the Cube's other face's effects in scientific terms) just in order to save a couple of charges you'll get back soon anyway.


It depends on the breath attack

SevenSidedDie has the correct principle in mind -- breath attacks and spells based on vapors or fogs (since the cube of force blocks fog) would be blocked by the cube of force effect in question, while those that are not would likely not be. However, the details get a bit trickier, due to the way things like acid breath and fire function.

Going by element:

  • Fire: Partially -- the combustion reaction takes place in the vapor phase, and only in the vapor phase. (If you had a tall Pyrex beaker full of diesel, and lit it on fire with a barbecue lighter, you'd see that the fire burns at the surface of the liquid, while the rest of the fuel remains unburned.) The other side of the cube of force would be plenty hot, though!
  • Acid: No -- the line-like acid-breath of a black dragon is more of a "caustic spitball" than a gas or a mist/fog (if it were a cone effect, I'd rule it as something more like an acid fog, but it's a line-effect).
  • Poison: Yes -- this is by RAW: the MM explicitly states that green dragons exhale "poisonous gas".
  • Cold/Ice: Partially -- while the actual fog of moisture generated by a "cone of cold" breath effect may not penetrate the cube of force -- the thermal effects still conduct through the cube and affect someone on the other side.
  • Lightning: No -- lightning breath either punches a hole through the cube of force due to dielectric breakdown, or jumps across it due to dielectric polarizability and breakdown of the air on the other side, as if the cube of force was the dielectric of an improvised capacitor.
  • Sleep Gas: Yes -- Again, this is by RAW.
  • Repulsion: No -- this is by RAW, as the effect is listed as "repulsion energy"
  • Slowing Breath: Yes -- this is by RAW again, the effect is listed as "exhales gas"
  • Weakening Breath: Yes -- yet again, this is by RAW, the effect is listed as "exhales gas"
  • Paralyzing Breath: Yes -- again, by RAW, same as the past two
  • Steam Breath: Yes -- a cone of "scalding steam" is a cone of gas or vapor (think of holding your hand right next to the nozzle on a teakettle).
  • Euphoria Breath: Yes -- again by RAW, this effect is listed as a "puff of euphoria gas"
  • Petrifying Breath: Yes -- once more, by RAW, this is listed as "exhales petrifying gas"
  • 5
    \$\begingroup\$ I believe this is exactly what SevenSidedDie meant by "Sciencing-Up". \$\endgroup\$
    – GreySage
    Sep 11, 2015 at 18:23

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