Everyone knows Dune focuses on this stuff called spice melange. Dune’s spice is found only on the desert planet Arrakis, which the emperor yanks from House Harkonnen and hands to House Atreides in a gambit to destroy them. Spice allows the spacing guild to navigate a safe path for interstellar travel. So everyone (in the entire fraking galaxy) sort of (completely, totally) depends on it.
So Dune’s spice = super important. It’s important to the barely-sorta-kinda-human guild navigators, who down it to chart interstellar travel, and to the Bene Gesserit, the druggy space witches who use it to do… well, lots of things, including steer a eugenics program. Dune’s spice is also important to the Fremen, who use it in both their daily life and religious rituals.
Incidentally, in the books, the spice is also important to everyone-freaking-one else in the galaxy, who take it for its “geriatric,” or life-prolonging, properties. Villeneuve seems to ignore this in Dune 2021, because insinuating that an entire galaxy stays constantly, mildly drug-addled is a hard sell from anyone but David Lynch. Probably because Lynch’s movies always seem a little drug-addled anyway (in a good way!).
In Dune 2021, Villeneuve shows Dune’s spice as golden unicorn dust that gives Paul Atreides (Timothée Chalamet) prescient visions. We see a crew mining it, and we know it comes… from the sand. In Arrakis. But it’s a little more complicated than that. Dune’s spice starts with sandtrout poop. It mixes with water deep under Arrakis’s sands and forms a fungal growth; this eventually creates massive pressure that leads to it exploding upwards. This results in a “pre-spice mass.” Through exposure to Arrakis’s excessive heat, sun, and wind, that pre-spice becomes Dune’s spice.
Everyone collects that Perfect Drug and uses it to trip their faces off, except they’re seeing the future/past instead of Lucy in the Sky with Diamonds. The Bene Gesserit utilize spice, in a roundabout way, as The Water of Life when they become Reverend Mothers and pass on their genetic memories, like the Fremen Sayyadina. The spacing guild uses it to navigate, and everyone else in the galaxy (though Villeneuve never says it) uses it to prolong their lives.
Oh, and taking enough of Dune’s spice will not only make someone a spice addict, but also turn their eyes electric blue. In the books, it’s a strange blue-on-blue that includes the whites of the eyes, but Villeneuve’s made the wise decision to keep it to the irises. So when we see Paul all blue-eyed in his prescient visions, he’s also all spice-addicted.
But really, here’s all you need to know:
The spice must flow.
He who controls the spice controls the universe.
He who can destroy a thing, controls a thing.