One day, Kesser the Curious, a 13th-level wizard with a 22 Intelligence score, pondered the question: can a rust monster really dissolve a cube of metal ten feet on a side with a touch?
For the advancement of arcane knowledge, Kesser obtained one rust monster and restrained it in a sturdy wooden cage. (Rust monsters aren’t very strong and their feeble bites—1d3—won’t even penetrate the hardness of wood. Even on a critical hit, which you typically can’t get on an object, it would only do one point of damage.)
Having obtained the rust monster, Kesser proceeded to cast wall of iron many times over the course of ten days until he had a ten-by-ten-by-ten-foot cube of iron. With each casting he made a ten foot by ten foot by three inch slab, cast shrink item to shrink it down to a square metal plate 7½ inches on a side and 3⁄16 of an inch thick. He could cast three wall of iron spells daily—four if he used his 7th-level spell slot, which he did—and shrink each down (for up to 13 days) to lay it down flat safely and stack them, until he had cast the spell forty times over ten days and stacked it all into a neat cube, ten feet on a side, which he then simply dubbed “The Cube”.
Satisfied, Kesser then released the slavering rust monster, which made a beeline for The Cube.
Now for some serious math.
A cube of iron ten feet on a side has 1,000 cubic feet of iron. The specific gravity of iron is 7.85, which means a cubic centimeter of iron weighs 7.85 grams. There are 28316.8 cubic centimeters in a cubic foot, so there are 28,316,800 cubic centimeters in The Cube. Multiplying that product by 7.85 yields 222,286,880 grams, or 222,286 kilograms, or a bit over 222 metric tons. (A metric ton is 1000 kilograms or about 2,200 pounds, 10% more than the short ton at 2,000 pounds.)
That’s…a lot of iron.
What Kesser did not know—or failed to take into account—is that the oxidation of iron is an exothermic reaction. In short, iron rusting releases heat. Normally, rusting occurs at a fairly slow rate, and this heat dissipates without notice.
How much heat?
Well, without going into too much extra math, 50 grams of iron rusting releases 409.2 kilojoules—that’s 409,200 joules—of heat. A joule is the amount of energy needed to move one kilogram (2.2 pounds) one meter (a bit over a yard). While that sounds like a lot, 50 grams is just 1.7637 ounces. That can’t be all that much, can it?
Well, not if it’s done over time, no.
But The Cube contains 222,286,880 grams of iron. Divide that by 50 and multiply the result by 409,200 and you get 1,819,195,825,920 joules.
All released in less than a six second round.
But that’s a number big enough to be meaningless. We need context. What should be used as a comparison? Well, the energy released by the detonation of a ton of TNT is commonly rated at 4.184 gigajoules. That’s 4,184,000,000 joules. So if we divide that into that…hmmm…
Kesser, the rust monster, and a good part of the countryside is immediately vaporized by a blast equal to 434.8 tons of dynamite exploding. The bomb that destroyed Hiroshima was the equivalent of about 15,000 tons, so this isn’t quite on the scale of a nuclear warhead, but still…
Kesser was highly intelligent but Wisdom was his dump stat.
Worse yet, the rust special attack on a rust monster is an extraordinary ability, which means it is supposedly nonmagical (Ha! Ri‑i‑ight…), so even an antimagic field wouldn’t prevent the blast.
Ahem. Rust monsters do not exist in my games. So don’t even think about it.
And be damn careful with the rusting grasp spell. Or, you know what, never mind. That’s magic; the spell vents the exothermic reaction safely to another empty plane of existence or something. Druids aren’t gonna blow up the landscape with a lousy 4th-level spell.
This has been another episode…of Experiments in Wizardry.
Somewhere, in some strange timeline, Gonzoran the Great and Mighty Wizard decided to tame the indomitable tarrasque. He wasn’t insane—well, not completely. He had a method to his madness.
He had been asked by a high priest of the sun god to assist in dealing with the creature’s latest rampage because he was considered the foremost expert on the tarrasque. He was, of course.
He knew the history of the creature’s prior attacks and was aware of its defenses, which were indeed formidable: a monumentally tough carapace that reflected ranged magical attacks in the form of beams, cones, rays, and magic missiles; very high spell resistance, and an ungodly ability to regenerate from virtually anything. Yes, it could be killed—but somehow, no matter how thoroughly destroyed it was, the thing always came back. It was like some malevolent deity or other powerful entity kept casting true resurrection to return it to life. This was probably true, but no one had ever actually determined the truth of it—including Gonzoran, who had tried.
It was clear that merely killing it wasn’t going to work. Anyway, he didn’t like to use the wish spell to “keep” it dead. It was a waste of personal resources.
So he prepared to try something…different.
Gonzoran was no stranger to creatures with monumentally high spell resistances; he had learned long ago how to bypass such resistances. (Arcane Mastery, Spell Penetration, Greater Spell Penetration, assay spell resistance, etc.) Creatures such as golems typically had unbeatable spell resistances…but the tarrasque was not a golem. He also knew that it had formidible natural toughness against almost any sort of attack…but not every sort of attack—not for an accomplished wizard like himself. He had superior intelligence, after all, even for a wizard.
He also considered the motivation of the creature: it hibernated—where, no one was ever sure; one would think that a ranger or druid would have long since tracked it back to its lair—for much of its existence, coming out when its hunger became insatiable.
For all its monumental power, the creature did have weaknesses: it was not very smart, for one. It couldn’t fly, and it had a limited ranged attack capability. It lacked any sort of true seeing ability, so Gonzoran knew he could approach it undetected by way of a superior invisibility spell, or even with lesser invisibility spells.
He prepared his spells and certain small magic items carefully and went to face the tarrasque alone. “Anyone else would be in the way,” he told the high priest. “They would be risking their lives unnecessarily. Stay back and I’ll signal you when it’s safe to approach.”
(If a DM disagrees, a simple spell to knock off that last point of Strength will settle the argument. It can’t be a spell that applies another Strength penalty because those typically don’t allow an ability to drop below 1. It will have to do an actual point of Strength damage, and it will have to be done daily to keep it from recovering that one point of Strength. If Gonzoran can do a point of Strength drain, that would be better; the creature couldn’t recover from that on its own. But all this doesn’t really matter for the purposes of this experiment.)
Having rendered the tarrasque helpless, the real work begins:
With sufficient time, Diplomacy checks, Gonzoran casting detect thoughts, and the high priest casting detect good, they should be able to bring the beast around and know that they have. At that point, Gonzoran can cast remove curse to restore the creature’s Strength. Swapping out the cursed ring for a regular ring of sustenance should be doable at this point if it is thought to be wise.
Then the high priest sponsors the terrasque into the Knights of the Sun as an initiate paladin…but that’s another story.
This has been another episode…of Experiments in Wizardry.