Interesting.
I was on the beach one day, before I ever smoked weed, or anything.
It was a rare day, the job I had at the beach, building houses during summers off, when I could take my swim suit and jump in the water after work. The air was a peaceful, balmy temp, no wind... The beach was clear of people, and the water was a peaceful green aqualescence.
I walked sleepilly out into the water... sank to my knees, and lay forward into the water. It was a sweet saline. And really, it felt like the air and the water were one. I lay facing down in the water... floating.
I guess they say in isolation chambers you are in a saline solution, that is the same temp as the air... and you start to see things....
I lay there for a few more seconds, put my hands over my eyes and drifted away...
Sleepily I walked to the sand bank, almost in a dream. :Laying back on the beach, with a slight berm behind me, I looked out into the ocean.
And there stood this being. I blinked, She flickered, but came back... This tall, tan, beautiful, creature with wild wispy red hair, full, glistening lips, deep hazel eyes, that gleamed this hungry, feral, overwelming power.
Her body was naked, her 6 breast heaved, she dripped with ocean water, her bush, a nest of red hair, glistened...
The power, and immense confidence in her shocked me.
And she disappeared.

Frank Herbert's books changed my life.
His ideas are transcendent, and explosive. More than anyone.
Asimov, Herman Hesse, Tolkien, etc are favorites too.
Now, to me, it is not a question of why dmt is called spice, only confusion over whether it should be THE spice...
It's fine with me, I'm sure there are other entheogens that can be called spice.

Some ideas by Herbert:
Bene Gesserit: ancestral memory holographically stored and activated by spice, and meditation. Ancestors can possess you if you don't rule them. This one reason men can't overdose on spice and survive like certain women.
There are some people who think Herbert was influenced by his knowledge of the Kurds, with their purple eyes, their ancient names, they are candidate for the Fremen.
Melange is produced by worms, spice blows from larvae attract adults.
A drowned larvae produces liquor poison that a Bene Gesserit can transform in her body, by communicating at a nano scale with chemicals.
Leto III bonds his skin to the worms, to live "forever" or long enough to effect his future for humanity.
Guild pilots are transformed physically in spice clouds.
Bene Gesserit had a genetic program that was to resolve after 1000s of years in Paul Atreides... but actually one generation later...
To have a male that can transform spice, and be the Kasswitch Haderach, or a Pilot that is advanced enough to go beyond piloting, and take humanity past the veil (seen in glimpses in Chapter house by cloned Duncan).
I should have read the wiki, lots of good info..
just had to add my 2 cents.