Among the many, many, many, many manymanymanymanymanymanymanymanyMANNNNNNNNYmany methods of execution in ancient times- and oh, they got creative back then- were a large number of methods you'd never see today for one reason or another. Usually that reason is excessive cruelty. Most of the methods used today, whatever your opinion on the death penalty is, at least try to just get the job over and done with with a minimum of drawn-out suffering. A lethal injection, a bullet to the back of the head. In ancient days, they really went to town on you. Being drawn and quartered, for example. That is not a 'minimum of suffering' punishment. That's intended to make you scream on your way out. A common feature of execution methods was, in fact, including a way of covering up the screams. Get some choir boys to sing hymnals while you burn someone at the stake. Lock someone up in a bronze replica of a bull rigged up to make the screams sound like those of a bull and roast it underneath (accounts agree that the inventor of this one wound up being the first person to have to go in it; accounts differ on whether he died in there or whether he was pulled out while still alive and then thrown off a hill).
Or, in the method we're trying to bring up here, make the victim unable to scream at all because he's too busy drinking the molten gold being poured down his throat. Gold's melting point, for reference, is 1,948 degrees Fahrenheit. Which means mucho ouchies. Among the historical figures who may have gone out like this: Spanish conquistador of Ecuador Pedro de Valdivia; captured men of Spanish conquistador of Nicaragua Pedrarias Davila; Roman emperor Valerian; the corpse of Roman general Marcus Licinius Crassus, the richest man of his day and the origin of the modern word 'crass' as he gained his fortune partially by buying the land of people whose houses were actively on fire at an increasingly deep discount; an assortment of people who thought that drinking it along with some crushed emeralds might fight off the Black Plague (spoiler alert: it doesn't).
There has actually been a study on what specific thing about pouring molten metal down one's throat is the thing that actually kills them. According to the study, conducted at VU University in Amsterdam in 2003, it was probably steam building up in the airways.
It would have to be the heat that does it, because gold, on its own, is safe for consumption; it's an officially approved food additive by the EU. It's inert, and won't be digested by a human body. You could theoretically eat as much of it as you wanted; it's just not going to provide any nutrition or anything. It's even been certified as kosher. It's safe enough that the disgustingly rich are willing to put it on their food, such as the $666 Douche Burger (actual name), just to be able to show off how rich they are. And a couple guys at Sri Lanka's international airport in Colombo were recently caught having eaten some for smuggling purposes, which, I'll be honest, was the original thing I was intending to focus on today but at this point it seems anticlimactic.
There's also these guys
who have something to say on the matter, but the word Illuminati comes
out in a hurry and it goes downhill fast into crazyville.
It's interesting, though, that the study on what kills you from drinking molten metal didn't use gold but rather lead (melting point: 621.5 degrees Fahrenheit), even though the test subject was the larynx of an already-dead cow. Lead is not inert, and can poison. That is why we have a little something called 'lead poisoning'. Of course, using lead instead of gold probably stemmed from the other major, non-cruelty-related reason that drinking molten gold is not used to kill someone these days: that is a very, very expensive way to kill someone.