Isn’t that what the OP referred to as too stupid? 
But was it a single cell of some gigantic organism forming, or a gigantic single celled organism splitting into two gigantic single celled organisms?
Come to think of it, Frank Herbert had a few books with living, sentient stars, too. And in Madeline L’Engel’s A Wrinkle in Time, Mrs. Who, Which, and Whatsit are manifestations of stars.
In the story “He Who Shrank” by Henry Hasse, our solar system is merely an atom in a larger universe. That larger universe has living creatures in it. Each solar system in that larger universe is merely an atom in a still larger universe. And so on. The same thing is true going the other way, so that each atom in our universe is a solar system in a smaller universe, etc.
This means that there are infinitely large living creatures, since the chain of larger universes goes on forever according to that story.
And in Rogue Star it turns out that many stars are intelligent. And in Olaf Stapledon’s The Star Maker most or all of them are.
In Starplex there are Jupiter sized creatures called Darmats, made of dark matter.
OK, show of hands: Has anyone but the two of us ever read that one? IIRC, the protagonist has already passed through hundreds or thousands of layers before reaching ours, so the beings of his original universe would have been something like 10[sup]1000000[/sup] times larger than our solar system (even if there aren’t any layers larger than where he started, which there probably are). And they’re undoubtedly natural, organic entities, and the story is undoubtedly science fiction. I can’t see any way to quibble with that, nor to top it.
I did; in fact I considered mentioning it ( because it was mentioned in a thread on another forum about this subject ). I just wasn’t sure if it qualified as “size” in the normal sense of the term.
Voyager had that thing that ate starships;
See also The Girl in the Golden Atom By Ray Cummings. IIRC, Cummings was an apprentice to Edison.
I’ll third this.
Budongs are gigantic.
“Planet” from Sid Meier’s Alpha Centauri is truly organic. It’s a fungus that grows in huge forest-sized swaths that also acts as a type of brain tissue. The bigger it gets, the smarter it gets. It periodically “blooms” to cover the entire surface of the planet, attains a god-like intellect, and promptly has 99.9% of its mass die because there’s no ecosystem left to sustain it (none of this “can magically survive in a vacuum” crap). The transcendence victory means that the humans living on Chiron use their high-tech gizmos to not only sustain Planet, but to link their minds to it. I think that the epilogue at least implies that this new Planet-humanity amalgam is able to grow well past biosphere size, and do so sustainably.
Read it. I think… Masters of Science Fiction three book set? Two short story books, one novelettas?
Marvel’s Beyonder filled an entire universe.
Oh yeah, living stars. Farscape had one that wanted to eat Talyn and Doctor WHo had one recently as well.
Nah, both creatures just lived in/on the stars, but weren’t stars themselves.
It’s fantasy not scifi, but in Simon Green’s Drinking Midnight Wine, all of the bodies in the solar system were sentient, including the sun. Don’t know if that counts though.
For sentient stars, there is also the classic Star Maker by Olaf Stapelton.
Yes, the Gigashadow was the last of the Insects, gigantic free-space dwelling lifeforms of tremendous physical and psionic power. It had formed the core of a Ceres-Luna sized planetoid before hatching, withstood blasts capable of destroying a planet, and was only destroyed when it collided with a wormhole it was too big to fit into.
There was the gigantic creature that landed on the Earth in “Heresies of the Huge God” by Brian Aldiss.
I too read it years ago in an Asimov anthology, I believe. I’ve always thought this idea was interesting.
I have – heck, it’s in the classic anthology Adventures in Time and Space.
It’s always bugged me, though – not only does the guy cause effects on his own atmos and sub-atomic structure from drinking a mere chemical, but he’s able to get himself over to a planet (when he finds that he’s shrunken down into that universe’s “interplanetary space” by “inchworming” his way along, totally ignoring conservation of momentum.
yeah, I know – I buy the premise of the story and object to those two issues? but the truth is that they bother me. It’s not science fiction, it’s fable.