If a College of Creation bard created 829 tons of iron on top of a guard shack, how much damage would it to do to people inside?

Question

In D&D 5e, RAW states that fall damage is 1d6 per 10 feet fallen, both to the object and to what it falls on.

In Tasha's Cauldron of Everything, the College of Creation bard, at 3rd level, can create any object/material within 10 feet of the bard (a few other conditions too). At level 14, one of the more limiting factors gets removed: Cost.

Iron has a value of 1 sp/lb. (according to the Trade Goods table). At this level, you can create a 15x15x15-foot object (3375 ft.³). That would be 1,658,796.75 lbs., or roughly 829 tons¹.
If this was created out of nothing on top of, say, a guard shack, how much damage should this do to the people inside that this weight lands on?
(Because let's face it, no structure is going to withstand an extra 829 tons out of mid-air, and there are way more dense materials in the RAW.)

---

1 - US tons or "short tons". This is equivalent to 751659 kg or 739.8 imperial/long tons.

Answer 1

Either 0 damage, or you cannot create the object.

The Performance of Creation feature states:

The item must appear on a surface or in a liquid that can support it.

Therefore, either the guard house is strong enough to support the weight of the object, causing no damage to the house and anyone inside, or you cannot create the object there at all.

Answer 2

At some point, you stop rolling...

If I could place the equivalent of about a ship on an area that's just as much as the ship's stern area, then you'd prompt this quote:

Damit Jim, I'm a doctor, not a necromancer. - Bones

Ok, seriously, even if gently placing the weight on the building, that's the mass of about 23 T62 tanks¹ stacked upon the poor building. Do you want to know what happens if you park one on a house? The same that happens if you drive it into it: It gets flattened. Stacking 22 more does not speed up the flattening in a manner that would be in any way perceivable for the human eye. ²

...because the house just isn't stable!

As a result, no building can be ever considered a surface that can support it to place that much weight on such a small area. As a result, you violate the feature's requirements:

The item must appear on a surface or in a liquid that can support it.

Since you can't place the cube in the first place, your feature fails because you have an invalid target.

---

1. A T62 weighs about 37 metric tons/41 short tons/36 long tons. You could substitute it with 84.5 Panzerkampfwagen II with a weight of 8900 kilos each.
2. That's what a good GM does: They apply Common Sense, or how German GMs call it: GMV (Gesunder Menschen Verstand). Common sense tells you, that if Hank gets backstabbed with a ballista, you splatter Hank all over the room even without a roll for damage. If someone ends under the tracks of a tank and is not intangible of sorts, they're dead, and you don't start to calculate damage.

Answer 3

Like Thomas Markov said in his answer:

The Performance of Creation feature states:

The item must appear on a surface or in a liquid that can support it.

Therefore, either the guard house is strong enough to support the weight of the object, causing no damage to the house and anyone inside, or you cannot create the object there at all.

But what if you made the object just heavy enough for the building to support it? Then oops your goliath barbarian friend goes and throws a big rock on top. This may also work better for getting away unharmed as being within 10ft of the falling building may be quite dangerous.

Answer 4

The crux of the question is "what counts as 'can support it'"?

The item must appear on a surface or in a liquid that can support it.

How is a bard supposed to know the maximum load a structure can support?

Taking this 'real physics' idea further, can the item be summoned on a patch of grass, knowing that the grass can't support it? But the ground underneath it is not available either, since it lacks empty space (there's grass in the way).
Pushing this argument: where is the limit?
If I summon a ton of lead on a wooden table, the table breaks, but the ground underneath holds: is it valid?
What if it is on a slab of stone on the ground? What if it is heavy enough to compact the ground on which I summon it? Technically, anything with even some weight will do so.

Can you summon an empty barrel made of potassium in a pond of water? The water could 'support it', it would float, but potassium instantly and violently reacts with water.

I mainly bring this forth because I did the math and you could theoretically summon (1.35+[cha] x 0.45)10^44 Joules worth of matter/antimatter mix as a 14th level creation Bard. This mass (1.5210^27 + [cha]x5.07*10^26kg ) would most likely not be supported by anything, as it would likely be the greatest gravitational well around (more like 'it' would be the one doing the supporting). At the same time, its constituent parts could be made unstable enough to decay faster than they could gravitationally or electromagnetically interact with the 'support' medium (top quarks, for example). I.E. they don't have time to 'touch' the ground before exploding with literally the power of a supernova, likely atomising everything within a light-year of the object.

The game is not a physics emulation, which renders the question impractical for the scope and scale of the game as it is made; while pushing it to an extreme can be fun, what problem in play are you trying to solve?

Apologies for going overboard with the logic in a fantasy roleplaying game, but hopefully this serves to illustrate that taking the ability to a 'logical' extreme goes beyond the limits of bounded accuracy, which leaves the "does it crush the guard shack" in the province of a DM ruling. (Most DMs would likely rule that "yes, the shack is crushed" and then play would carry on).