Do You Wanna Kill a Planet?

[Tinkerer]

So I was thinking the other day about the amount of power that a player should have and one of the things which sprang to mind was that a player generally (there are exceptions) shouldn't have enough power to destroy a planet. If there is a method of doing this then it's normally an indication that something has gone wrong in the game design. I was curious about methods of destroying the world across several systems. If I could lay down some ground rules here:

1) All PC abilities must be drawn from valid PC choices of the main books and setting books. No adventure books (looking at you Apocalypse Stone).

2) No GM adjudicated abilities. Theoretically a wish spell may be able to destroy the world in D&D however I think everyone can agree that would be a pretty dumb idea that no GM would allow.

3) It should result in the death of just about every creature on the world. Creatures able to flee the planet may survive and certain super tough entities like physical gods may be able to tank it but we are talking about a general sort of apocalypse here.

4) It shouldn't require equipment that the PCs don't normally have access to.

So far I recall two that I've run across.

1) FATAL - Not surprisingly the system which is the punchline of bad design has one built in. This one is somewhat unique in that it isn't an accident on the part of the developer but quite intentional, although the activation of it is likely to be accidental. FATAL has Fatal, the 10th level spell which instantly kills all life on the planet. I haven't dived into the rules far enough to know how difficult it is to cast (it looks insanely difficult and for good reason) however every time you cast a spell in FATAL there is a small chance that you will accidentally cast this spell instead and end the world.

2) Savage Rifts - Okay this one requires a bit more set up. I'm AFB at the moment so you'll have to excuse my lack of specifics. In order to perform this one you will require at least 7-8 players all of whom will have to be Ley Line Walkers (mages for those who aren't familiar). The Ley Line Walker has an ability which allows them to teleport to any Ley Line Nexus which they can see, this is altered from the original where it had to be connected to the Ley Line you were currently on. I don't think the designers realized that in Rifts Earth at the right times you can see the Ley Lines on the moon. So step 1, teleport your party to the moon! Just make sure they have protection.

Step 2: Have all of the Ley Line Walkers buff a single Ley Line Walkers Spirit (or Smarts I can't recall) stat. You can then use Mega-Telekinesis to MOVE THE ENTIRE MOON! This is due to 2 factors. 1) Buffs from one particular spell explicitly stack in Savage Worlds. 2) Telekinesis allows you to move objects with your mind as though your Spirit (or Smarts, again I'm AFB) was your Strength stat. The Strength stat doubles what you can move per point of increase when you go above the top of the chart. And since they Ley Line Walkers are sitting on a nexus point they can keep the spell going for an unlimited amount of time. Which is good because it will require approximately 1 month to pilot the moon right into the Earth, not accounting for the fact that eventually Earth will start to pull it in via gravity. Now I am familiar with the Roche limit however there are ways around it depending on the angle and speed of approach. So long story short we would be looking at an event 1000x bigger that the one which killed the dinosaurs.

Needless to say I ruled that this particular spell no longer stacks in my campaigns.

So what other methods have people found for destroying entire gaming worlds? I seem to recall a method in 3.5 of inflicting unlimited damage by taking unlimited damage but I can't remember the specifics. Call of Cthulu is an obvious choice however I can't recall anything concrete in there.

NOTE: This is a totally passive and fun post. Feel free to derail away debating the feasibility of any possibilities so long as it's fun.

Worlds Definitely Destroyed:
Savage Rifts - I throwa da moon
F.A.T.A.L. - The titular spell
D&D 3.X - So many methods see this thread http://www.giantitp.com/forums/showt...-it-a-Handbook
Dark Heresy - Psyker Fire Storm
GURPS - The M.U.N.C.H.K.I.N. http://forums.sjgames.com/showthread.php?p=239055
Carnage 3:16 - Planet Killing Missiles are standard gear if you attain a high enough rank
Mutants and Masterminds 3e - Massive Area Expulsion Power, or Push the Planet Into the Sun, or being one of the few systems to actually stat the Earth (kudos to that system for that), or... look there's lotsa ways
DC Heroes - Stat'd Earth, purchasable abilities to destroy it as long as you are at least a moderately established hero.
D&D 5e - Simulacrum+Wish.

Worlds Maybe Destroyed: Requires additional research or conditional
Chuubo's Marvelous Wish-Granting Engine - Only if the planet is spiritually unimportant
D&D 4e - Allabar. Sure it's a planet but it explicitly says you cannot fight it in it's planet form
SLA Industries - Not familiar with this system however from the sounds of Wraith's post it looks like you require GM fiat on either front. If anyone is familiar please check out Wraith's post on page 2.
Dark Heresy - Exterminus. I don't think this is something the players themselves normally control? I could be wrong? I don't have this one.
Star Wars - Planetary Bombardment. Same as above I don't think it's within the scope of a normal campaign to gain access to the equipment to do this.

Standard Methods Methods which work across multiple systems
Accelerating a space ship to relativistic speeds and crashing it into the planet.
Achieve immortality, outlive the planet.

Things which have come up which won't work
Sphere of Annihilation in various editions of D&D at the core of the Earth. Takes too long (longer than your character's likely life), too easy to detect, too easy to disrupt.

[Evoker]

I think this would work in 3/3.5e D&D:

Create a repeating magic trap of Widened Disintegrate. Surround it on all sides with permanence'd wall of force except for a arrow-slit for it to target through. Have it be built to trigger constantly, disintegrating the ground below it. Wait for it to reach the molten core of the planet. Massive super volcano eruption.

Alternatively, I think there's something to do with meta-breath feats. Widen and make more powerful X10000. Kill everything on the planet.

[LordCdrMilitant]

I used the greater demiplane of projectile acceleration in one Pathfinder campaign.

Use a Permanency Greater Demiplane that is in vacuum and loops around at the edges, which are specific properties that you can add to your demiplane, and you can double g as well to halve your weapon's "charging time".

When your dense object is travelling fast enough, you can Gate it into the planet for a cataclysmic impact.



Of course, I'm fairly certain more of our party could survive that particular apocalypse, assuming we weren't at ground zero [and even then, at least some of us could survive ground zero], than couldn't, so it's not really a big deal.




And, of course, there's always multistage cyclonic torpedoes, virus bombing, atmospheric incinerator ordnance, and all the other Exterminatus techniques that a Dark Heresy party can employ, and your Star Wars party can, hypothetically, base-delta-zero a planet, and so on.

[Max_Killjoy]

I used the greater demiplane of projectile acceleration in one Pathfinder campaign.

Use a Permanency Greater Demiplane that is in vacuum and loops around at the edges, which are specific properties that you can add to your demiplane, and you can double g as well to halve your weapon's "charging time".

When your dense object is travelling fast enough, you can Gate it into the planet for a cataclysmic impact.

Magic mass accelerator. Relativistic, if applicable in the setting. Ouch.

[Tinkerer]

I used the greater demiplane of projectile acceleration in one Pathfinder campaign.

Use a Permanency Greater Demiplane that is in vacuum and loops around at the edges, which are specific properties that you can add to your demiplane, and you can double g as well to halve your weapon's "charging time".

When your dense object is travelling fast enough, you can Gate it into the planet for a cataclysmic impact.

snip

And, of course, there's always multistage cyclonic torpedoes, virus bombing, atmospheric incinerator ordnance, and all the other Exterminatus techniques that a Dark Heresy party can employ, and your Star Wars party can, hypothetically, base-delta-zero a planet, and so on.

Interesting. That sounds like it would be an cool thing to crunch some numbers on (well cool for someone who likes determining how long it would take an elephant to accelerate at 2g to be able to destroy a planet). I have used circle portals to accelerate something's mass before but only in an atmosphere where there is a hard limit.

I haven't played Dark Heresy yet although I am familiar with the universe so I can't really comment there but I know in Star Wars assuming standard character generation procedure that's more like asking someone else to destroy the world rather than destroying it yourselves (see requirements 2 and 4).

EDIT:

I think this would work in 3/3.5e D&D:

Create a repeating magic trap of Widened Disintegrate. Surround it on all sides with permanence'd wall of force except for a arrow-slit for it to target through. Have it be built to trigger constantly, disintegrating the ground below it. Wait for it to reach the molten core of the planet. Massive super volcano eruption.

Alternatively, I think there's something to do with meta-breath feats. Widen and make more powerful X10000. Kill everything on the planet.

Meant to address this one too. Disintegrate can't be widened as it's a ray right? Were you meaning to use another term? It would also need to be widened to an extreme level in order to create a super volcano. But that would require some more research. I highly doubt that a super volcano would result anyway (those are caused by pressure and a straight hole suddenly put in the earth wouldn't really result in that). I don't know about the meta-breath feats but I'm assuming by your X10000 that you are saying it's something which can be applied infinitely? Because X10000 isn't really going to cut it.

[Chijinda]

Interesting. That sounds like it would be an cool thing to crunch some numbers on (well cool for someone who likes determining how long it would take an elephant to accelerate at 2g to be able to destroy a planet). I have used circle portals to accelerate something's mass before but only in an atmosphere where there is a hard limit.

I haven't played Dark Heresy yet although I am familiar with the universe so I can't really comment there but I know in Star Wars assuming standard character generation procedure that's more like asking someone else to destroy the world rather than destroying it yourselves (see requirements 2 and 4).

Dark Heresy exterminatus is a thing, though, it is TECHNICALLY feasible to be a one-man Armageddon in Ascension, via a bit of combos for an Ascension-level Psyker. While I don't have my Ascension rulebook on-hand, it basically involves a flamestorm that continuously expands until the power ends. The Psyker in question suffers damage and fatigue every turn they continue to maintain it, but that is easily compensated with the CRB Regeneration power. Combine those two, and couple that with a Primaris Psyker's absurd Willpower Bonus (due to access to Unnatural Willpowerx3, which could easily give them a WPB of over 20) and Psy Ratings allowing them to fetter almost all their powers and still reliably get them to work, and a Psyker could very easily achieve an infinitely expanding firestorm. It's a little bit game-y but it would work (it's also a premier showing of how terrible Ascension's design is).

[Tinkerer]

Dark Heresy exterminatus is a thing, though, it is TECHNICALLY feasible to be a one-man Armageddon in Ascension, via a bit of combos for an Ascension-level Psyker. While I don't have my Ascension rulebook on-hand, it basically involves a flamestorm that continuously expands until the power ends. The Psyker in question suffers damage and fatigue every turn they continue to maintain it, but that is easily compensated with the CRB Regeneration power. Combine those two, and couple that with a Primaris Psyker's absurd Willpower Bonus (due to access to Unnatural Willpowerx3, which could easily give them a WPB of over 20) and Psy Ratings allowing them to fetter almost all their powers and still reliably get them to work, and a Psyker could very easily achieve an infinitely expanding firestorm. It's a little bit game-y but it would work (it's also a premier showing of how terrible Ascension's design is).

Neat, that is a lot more of a PC apocalypse than asking your superiors to wipe out the planet. I'm gonna jot that one down.

[Drakevarg]

Strictly speaking, "GM-adjudicated abilities" are the only way to kill a planet in most systems simply because most systems don't have rules for anything remotely at that scale. In 3.5 (for example), planets have no stats and thus can't be destroyed unless the DM says so. A demiplane railgun would deal 20d6 and not a point more, because it's gravity-accelerated and thus would use falling object rules. And of course projectile weapons don't generally have splash damage so they would smush whatever you aimed it at and affect nothing else.

Physics and game systems don't cooperate. Attempting to make the latter simulate the former is almost always arbitrary (X event does Y damage, so an event that is ten times as big as X should do 10Y damage) and contradictory (but a different rule has a similar event do Z damage instead, meaning that extrapolating from that event would have a totally different outcome).

Which isn't to say you can't kill a planet in these systems. Just saying that the rules won't support it because the rules aren't and never pretend to be laws of physics.

[Tinkerer]

Strictly speaking, "GM-adjudicated abilities" are the only way to kill a planet in most systems simply because most systems don't have rules for anything remotely at that scale. In 3.5 (for example), planets have no stats and thus can't be destroyed unless the DM says so. A demiplane railgun would deal 20d6 and not a point more, because it's gravity-accelerated and thus would use falling object rules. And of course projectile weapons don't generally have splash damage so they would smush whatever you aimed it at and affect nothing else.

Physics and game systems don't cooperate. Attempting to make the latter simulate the former is almost always arbitrary (X event does Y damage, so an event that is ten times as big as X should do 10Y damage) and contradictory (but a different rule has a similar event do Z damage instead, meaning that extrapolating from that event would have a totally different outcome).

Which isn't to say you can't kill a planet in these systems. Just saying that the rules won't support it because the rules aren't and never pretend to be laws of physics.

Yes-ish? I believe that they use terminal velocity as a term in the 3.5 book... and I just checked the SRD and they do not. Neat. So you are correct and it would max out at 20d6 RAW. A planets stats can be extrapolated however. We know the rough size and mass of the planet and they do provide systems for calculating the damage capacity of inanimate objects. So they have stats, just not listed ones. And I know Physics and game systems don't mix, that's the fun of these thought experiments. It's also neat to see which systems have infinite recursive loops.

[Drakevarg]

A planets stats can be extrapolated however. We know the rough size and mass of the planet and they do provide systems for calculating the damage capacity of inanimate objects.

As previously mentioned, dice systems and extrapolation don't play nice together. And we don't really have any way of knowing the size and mass of the planet because it's similarly not specified - "basically Earth-like" is a pretty broad description that itself runs on presumption and fiat. The world could just as easily be flat, manifestly traversing space on the back of a giant turtle, be hollow inside, all sorts of things that would throw calculations off without losing the superficial resemblance to Earth to people actually standing on it.

[Lord Torath]

I think this would work in 3/3.5e D&D:

Create a repeating magic trap of Widened Disintegrate. Surround it on all sides with permanence'd wall of force except for a arrow-slit for it to target through. Have it be built to trigger constantly, disintegrating the ground below it. Wait for it to reach the molten core of the planet. Massive super volcano eruption.

How does this work? I was under the impression that Disintegrate had a limited range (an order of magnitude or two less than a mile). Is the idea that this force-box/wand combo disintegrates the ground beneath it, falls down, then again disintegrates the ground, falls, and repeats until it reaches the core? Or at least the mantle? Because our crust isn't that strong. Your hole would collapse on top of your force box before it's fallen more than 100 feet or so, and your hole would self-plug all the rest of the way down to the core. Granted, you're still destroying 1000 cubic feet of planet every round, but Earth is big¹, and it will take billions of years before you even start to make a dent. But you're not going to be getting a super volcano out of a 10x10 hole.

It's a little bit game-y but it would work (it's also a premier showing of how terrible Ascension's design is).

No worries. That is entirely the point of this thread!

1. Citation needed.

Okay, okay, you got me. I did the math. Assuming the Earth is a perfect sphere (it's close enough for this example) with a radius of 3963.19 miles, it's got a volume of 3.838x10²² cubic feet. That's 3.838x10¹⁹ disintegrates. At one per six seconds, that's still 7.3x10¹² years to disintegrate it all. A billion years after dropping your disinte-box, you've reduced the total volume of the planet by roughly a percent of one percent of the total.

[Tinkerer]

As previously mentioned, dice systems and extrapolation don't play nice together. And we don't really have any way of knowing the size and mass of the planet because it's similarly not specified - "basically Earth-like" is a pretty broad description that itself runs on presumption and fiat. The world could just as easily be flat, manifestly traversing space on the back of a giant turtle, be hollow inside, all sorts of things that would throw calculations off without losing the superficial resemblance to Earth to people actually standing on it.

Yep, that's definitely true and I've given players crap before for assuming that physics has a place in the D&D world. The two specific environments which I gave *were Earth though*. Thus we can assume that crashing the moon into it will destroy it. And on the other one it simply kills everyone so the type of planet doesn't matter.

For 3.5 you can pick a particular world which is defined or you can go with an approach which provides theoretically infinite damage under the assumption that infinite damage will do enough to destroy the world. Indeed I still vaguely recall something from 3.5 which allows you to deal damage based on how much damage you receive and something else which allows you to receive infinite damage.

Additionally note that I said no GM adjudicated abilities, assigning stats to Earth isn't an ability. I mainly introduced that rule as a way to block abilities which require an excess of GM fiat such as wish or meta-currencies.

[Evoker]

How does this work? I was under the impression that Disintegrate had a limited range (an order of magnitude or two less than a mile). Is the idea that this force-box/wand combo disintegrates the ground beneath it, falls down, then again disintegrates the ground, falls, and repeats until it reaches the core? Or at least the mantle? Because our crust isn't that strong. Your hole would collapse on top of your force box before it's fallen more than 100 feet or so, and your hole would self-plug all the rest of the way down to the core. Granted, you're still destroying 1000 cubic feet of planet every round, but Earth is big¹, and it will take billions of years before you even start to make a dent. But you're not going to be getting a super volcano out of a 10x10 hole.

Good point. You need to add a repeating magic trap of Extended wall of force. Have it brace the shaft with the walls.

[Lord Torath]

Good point. You need to add a repeating magic trap of Extended wall of force. Have it brace the shaft with the walls.

Even then, the lava will quickly (1-2 weeks) form a plug over the top of the hole. And if you're "wall-of-forcing" as you go down, you're sealing your hole against all that nice hot magma you're trying to get to the surface. No volcano for you!

[Evoker]

Even then, the lava will quickly (1-2 weeks) form a plug over the top of the hole. And if you're "wall-of-forcing" as you go down, you're sealing your hole against all that nice hot magma you're trying to get to the surface. No volcano for you!

no, you wall the edges of the pit only. the pressure at the earth's core should cause the lava to move up rapidly.

Cross-section Diagram:

======
=++++=
=+~~+=
=+~~+=
=++++=
======

= is the edges of the disintegrated ground
+ is the wall of force
~ is magma.

does that make sense?

[Khedrac]

Gold box Immortal D&D, in addition to the sentient planets you get the four Elemasters which are the ultimate immortal elementals.
Each one has stats of 75, which for strength gives a base 75% chance to throw something (amongst other things).
The twist is that the elemasters do not take a penalty on stat checks involving their own element, so the fire elemaster has a 75% chance to throw a star at something - goodbye planet.
The Earth elemaster can use a large rocky planet and the Air elemaster a gas giant - not as effective as a star, but not shabby.
Of course, PCs won't be the elemasters so they get to take difficulty checks and cannot do this, so this is another GM only technique.

[Max_Killjoy]

no, you wall the edges of the pit only. the pressure at the earth's core should cause the lava to move up rapidly.

Cross-section Diagram:

======
=++++=
=+~~+=
=+~~+=
=++++=
======

= is the edges of the disintegrated ground
+ is the wall of force
~ is magma.

does that make sense?

Yes.

But the magma/lava still cools, solidifies, builds up, and forms a plug, eventually, unless you take steps to keep the top of the hole open.

[Evoker]

Yes.

But the magma/lava still cools, solidifies, builds up, and forms a plug, eventually, unless you take steps to keep the top of the hole open.

the magma should only be able to solidify far from the hole once the other lava is not pushing it up, right?

[Tinkerer]

no, you wall the edges of the pit only. the pressure at the earth's core should cause the lava to move up rapidly.

Cross-section Diagram:

======
=++++=
=+~~+=
=+~~+=
=++++=
======

= is the edges of the disintegrated ground
+ is the wall of force
~ is magma.

does that make sense?

I have doubts that it would act as a planet destroying super-volcano though. I mean we've put holes that size in the crust before several times. Volcanoes are a combination of several different factors and this only provides one of them. You would get some magma spewing out but nothing planet destroying.

[Drakevarg]

Yes.

But the magma/lava still cools, solidifies, builds up, and forms a plug, eventually, unless you take steps to keep the top of the hole open.

Also, doesn't disintegrate only reduce things to dust? Most of it dissipates so in normal circumstances it's a non-factor, but when you're trying to dig a 3900 mile pit I have to imagine eventually you'll be firing disintegrate beams mostly at pre-disintegrated dust.

[Evoker]

Also, doesn't disintegrate only reduce things to dust? Most of it dissipates so in normal circumstances it's a non-factor, but when you're trying to dig a 3900 mile pit I have to imagine eventually you'll be firing disintegrate beams mostly at pre-disintegrated dust.

It's unclear. creatures leave behind a trace of fine dust, but it's unclear whether objects do or not.

[InvisibleBison]

I don't know about the meta-breath feats but I'm assuming by your X10000 that you are saying it's something which can be applied infinitely? Because X10000 isn't really going to cut it.

Meta-breath feats let you apply effects to your breath weapon in exchange for increasing the recharge time, and can sometimes be applied multiple times to a single breath. The two that let you destroy the world are Enlarge Breath, which lets your breath weapon affect a larger area, and Lingering Breath, which creates a lasting cloud that re-applies your breath weapon's effect. Both of these feats can be applied any number of times to a breath weapon, allowing a dragon to create a cloud that engulfs the entire world and lasts for years. Best used by a shadow dragon, whose breath weapon inflicts negative leves, or a pyroclastic dragon, whose breath weapon is a disintegrate effect.

[Lord Torath]

no, you wall the edges of the pit only. the pressure at the earth's core should cause the lava to move up rapidly.

Cross-sectionPlan View (looking down from above) Diagram:

======
=++++=
=+~~+=
=+~~+=
=++++=
======

= is the edges of the disintegrated ground
+ is the wall of force
~ is magma.

does that make sense?

That actually looks like a Plan View to me (view from above?)

Here's an actual Cross Section view (# = Disinte-Box, .. = air-filled interior of Wall of Force-reinforced hole)
==+..+==
==+..+==
==+..+==
==+..+==
~~+..+~~
~~+..+~~
~~+..+~~
~~+..+~~
~~+#+~~
~~~~~~~
~~~~~~~
~~~~~~~

You've always got a wall of force between you and the magma, whether it's the ones you're putting to the sides as you go down, or it's the one with the teeny hole for the disintegrate beam to shoot through.

Really, though, you'd never get past the first place you encountered magma. Rock is dense stuff, and so is liquid rock. Your disinte-box is mostly air and magically weightless walls of force, and the magma is too dense for it to sink through. I imagine the magma would push you back up through the tube until you hit some sort of equilibrium point where the magma is raising at 10' per six seconds and, your disinte-box is disintegrating it back down every 6 seconds.

[Tinkerer]

Meta-breath feats let you apply effects to your breath weapon in exchange for increasing the recharge time, and can sometimes be applied multiple times to a single breath. The two that let you destroy the world are Enlarge Breath, which lets your breath weapon affect a larger area, and Lingering Breath, which creates a lasting cloud that re-applies your breath weapon's effect. Both of these feats can be applied any number of times to a breath weapon, allowing a dragon to create a cloud that engulfs the entire world and lasts for years. Best used by a shadow dragon, whose breath weapon inflicts negative leves, or a pyroclastic dragon, whose breath weapon is a disintegrate effect.

Wow, I do feel dumb for not checking the archives. There is a collection of 3.5 world ending effects at http://www.giantitp.com/forums/showt...-it-a-Handbook Yep that is the very first one on the list haha.

[Lord Torath]

Meta-breath feats let you apply effects to your breath weapon in exchange for increasing the recharge time, and can sometimes be applied multiple times to a single breath. The two that let you destroy the world are Enlarge Breath, which lets your breath weapon affect a larger area, and Lingering Breath, which creates a lasting cloud that re-applies your breath weapon's effect. Both of these feats can be applied any number of times to a breath weapon, allowing a dragon to create a cloud that engulfs the entire world and lasts for years. Best used by a shadow dragon, whose breath weapon inflicts negative leves, or a pyroclastic dragon, whose breath weapon is a disintegrate effect.

How long of a recharge time do you need to affect 3.84x10²² cubic feet?

[Lalliman]

Maybe not directly world-ending, but there's a ridiculous loophole you can do in D&D 3.5 that'll probably give you some potential for world-destroying.

The Book of Vile Darkness has a prestige class called Cancer Mage, which ignores all of the negative effects of diseases. There's also (from another source, not sure what) a disease called Festering Anger, which every day from its onset causes 1d3 Constitution damage and a +2 bonus to Strength. The Cancer Mage ignores the Con damage while gaining the Str bonus.

So basically: be a Cancer Mage, be infected by Festering Anger, then wait about a year. You now have 700 Strength, which is more than enough to lift the entire Earth.

Obviously, you'll need to be a bit inventive, since punching the ground will merely displace the dirt, and trying to lift the Earth will just be you doing a handstand. But you can probably figure out a way to turn a mountain into a meteorite, or to punch some volcanoes and make them erupt.

[Tinkerer]

How long of a recharge time do you need to affect 3.84x10²² cubic feet?

Not sure if it's that area but apparently only 10 years. That doesn't sound right but I can't math it right now.

EDIT: Read a little further in the post and it doesn't appear to be valid based on the fact that the specific Metabreaths which allow stacking state that and Enlarge Breath doesn't. So it's a little grey.

EDIT 2: Removed due to unclear reading

[InvisibleBison]

How long of a recharge time do you need to affect 3.84x10²² cubic feet?

To create a cloud of disintegrating energy that engulfs a planet and lingers for ten years would require a Young pyroclastic dragon to put its breath weapon on cooldown for 20 years, 293 days, 8 hours and 1d4 rounds.

1d4 rounds is the base recharge time.
Applying Spread Breath to make the breath weapon into a 20-foot radius spread is 2 rounds.
Using Enlarge Breath to increase the radius to 8,000 miles is 4,223,998 rounds.
Using Lingering Breath to make the breath weapon linger for 10 years is 20 years (1 round of lingering = 2 rounds recharge time).

EDIT: Read a little further in the post and it doesn't appear to be valid based on the fact that the specific Metabreaths which allow stacking state that and Enlarge Breath doesn't. So it's a little grey.

The text of the feat doesn't say that Enlarge Breath can stack, but the explanation of how some metabreath feats can stack uses Enlarge Breath as an example, so it is an ambiguous situation.

[Max_Killjoy]

To create a cloud of disintegrating energy that engulfs a planet and lingers for ten years would require a Young pyroclastic dragon to put its breath weapon on cooldown for 20 years, 293 days, 8 hours and 1d4 rounds.

1d4 rounds is the base recharge time.
Applying Spread Breath to make the breath weapon into a 20-foot radius spread is 2 rounds.
Using Enlarge Breath to increase the radius to 8,000 miles is 4,223,998 rounds.
Using Lingering Breath to make the breath weapon linger for 10 years is 20 years (1 round of lingering = 2 rounds recharge time).



The text of the feat doesn't say that Enlarge Breath can stack, but the explanation of how some metabreath feats can stack uses Enlarge Breath as an example, so it is an ambiguous situation.

Does the long cooldown come before or after the actual usage?

[InvisibleBison]

Does the long cooldown come before or after the actual usage?

The cooldown comes after the usage.