A Science Fiction Trilogy by John Varley describing humanity's encounter with a moon-sized alien, and the indigenous aliens that live upon it.
In the first book, titled Titan, a space expedition to Saturn Gone Horribly Wrong when the ship gets swallowed by one of the satellites and find themselves inside a living planet with a god complex. The crew all get separated at first, and start looking for each other. They find useful aliens in the form of Smilers, six legged kangaroos you can eat without killing; Titanides, musically oriented, friendly centaurs, and Blimps; living dirigibles that willingly serve as transports.
The second book, Wizard, is set some decades later. Some characters return from the first book, but two new cast members are introduced: Chris Major, who suffers from psychotic episodes; and Robin, a witch from an all-female space colony who has a seizure disorder. Both come to Gaea to be healed, but get sucked into the original cast's plot to overthrow the crazed Genius Loci that runs the world.
The third book, Demon, brings back most of the cast from Wizard. It describes the final war between the human refugees and the Genius Loci.
This trilogy provides examples of:
- Affably Evil: Gaea, at least until the last book when it's more Faux Affably Evil.
- A Form You Are Comfortable With: Gaea manifests as a plump, homely, slightly dotty but cheery and friendly little old lady. Until Demonwhen she switches to a fifty-foot-tall replica of Marilyn Monroethat is.
- Batman Gambit / Villain Ball: The world's 'consciousness', Gaia, is looking for a replacement. She's been holding the Villain Ball, doing perverse and nasty things for a long time, in hopes that a Worthy Opponent would appear and take over before she becomes completely senile.
- Chubby Chaser: "Fat Fred," at least by angel standards.
- Did You Just Punch Out Cthulhu?: Once at the end of the second book, when Cirocco actually punches the incarnation of Gaea out. Again, at the end of the third book, when a team effort manages to completely kill Gaea.
- Eldritch Abomination: All of the regional brains, and Gaea proper.
- Exotic Equipment: The Titanides, being centaurs, have one set of human-sized genitalia in the front (male or female), and both sets of horse-sized genitalia in the back (male and female). "Rear sex" is casual, but "front sex" carries an enormous amount of emotional baggage.
- Fantasy Contraception: In Wizard, Gaea tries to exert her control over Cirocco by making her saliva the only substance able to take Titanide eggs to the next level of conception. This leads to her image involving all sorts of drunken dysfunction.
- Genius Loci: Gaea, and she's neither a nice nor a sane one. The twelve "ring minds" at the bottom ends of Gaea's spokes could also qualify.
- Global Airship: The Blimps, especially Whistlestop. A 3000-year-old, living Cool Airship.
- Half-Human Hybrid: the Titanides, kinda.
Gabby: "I've heard of parallel evolution, but from the waist up?"
- Exactly half human, in some ways, as lampshaded by Gabby in Titan.
- And half human in other ways in Wizard, after it's learned that humans can breed with Titanides, and that one of the Titanides is actually Cirocco's grandson.
- Improvised Microgravity Maneuvering: At the end of Wizard. The hub of Gaea is practically in zero gee, and Cirocco needs to get herself out of there and back down to the rim in a hurry.
- Interspecies Romance: Several examples (both sexual and non-sexual) with Titanides and humans, and at least one with an angel and a human.
- Living Gasbag: The Blimps are floating sapient creatures, and often serve as a means of transportation. The one known as Whistlestop gives our heroes a ride in the first book.
- The Symbiote: The Blimps rely on small, ape-like creatures living in their stomachs to "preprocess" the leaves and branches the Blimps eat. The Blimps actually digest the droppings from the ape creatures after the apes eat the foliage.
- Mars Needs Women: "Fat Fred," an angel, prefers human women to his own species. Tzigane, a Titanide, is stated to have a habit of "chasing human tail."
- Our Angels Are Different: Nothing supernatural about them; "angel" is simply the term applied to several different species of Winged Humanoid.
- That said, Gaea's original inspiration was the "traditional" depiction of angels, modified by the limits and demands of real physics and biology.
- Our Centaurs Are Different: Titanides have an incredible variety of possible appearances (smooth-skinned, short-furred, long-furred, any imaginable color and pattern). Above the waist, they all appear as sexy human women, complete with boobies, female and male both. They're also all hermaphrodites (although they identify themselves as either male or female) with three sets of genitalia (the frontal set determines gender identity, along with whether or not they can reproduce via parthenogenesis). And they can interbreed with humans.
- Physical God: Gaea is a planet sized creature with inhabitants that she created.
- Planet Spaceship: Gaea and her brood are living space habitats large enough to be mistaken for additional moons of Saturn.
- Ring World Planet: The Titans.
- Sanity Slippage: Gaea suffered this long ago but it becomes more and more obvious through the trilogy. By Demon she's not even hiding it anymore.
- Superpower Lottery: Gaea does this in a half-assed fashion. Usually, it's Translator Microbes (Titanide song or blimp speech), but April is transformed into a compulsively solitary angel.
- Take Me to Your Leader
- The Good Guys Always Win: Discussed in Demon. Because Gaea is something of a sucker for cheesy classic Hollywood movies, she has internalized their cliches — and by this point she's decidedly playing the villain. The tricky part is if that she by and large expects the "good guys" to play by the movie rules as well... and if she considers Circocco and friends to be "good guy" enough to beat her.
- Tsundere: Chris and Robin's daughter Nova is a type A of Helga Pataki caliber.
- Winged Humanoid: The angels.
- Zero-G Spot: Right out of the starting gate in chapter 2 of the first book.