Comic artist Jack Kirby was extremely prolific, and he didn't stop at portraying his cranium-blowing cosmos in pen and ink. In the 60's he began experimenting with collages, initially as a hobby, but then he began to integrate them into his published work.
In Mark Evanier's book, Kirby: King of Comics, it's recounted that Kirby's friend Gil Kane described him as a "mad chemist", combining things no one had combined before. He would sit for hours, clipping photos out of magazines, combining them to create fantastic scenes and compositions.
Beginning in 1964 with The Fantastic Four, his collages began to show up in his comics. He intended to illustrate the entire world called the Negative Zone entirely through collage, but had to abandon the idea due to time and page count restraints. Still, Kirby managed to work collages into the Fantastic Four.
The crappy printing and tree-bark paper of the 60's and 70's didn't do justice to many of the collages (though it now adds a nostalgic fever dream quality), which could explain why the practice didn't really take off. Kirby's collage work now gets the props it deserves, and is seen as being far ahead of it's time.
In 1970, Kirby landed at DC Comics with a stint on Superman's Pal Jimmy Olsen. As the storylines became trippier, he gave free reign to his psychedelic streak. In issue #137, Jimmy and Supes take a trip through the Solar-Phone. As a fellow Solar-Phone tripper describes:
Man! This is cool! It's like a musical—and everybody's in it! Includ'n me, flippa-dippa!
Kirby's collages were used to illustrate his alternative realities, universes, and multiverses. The medium fit with his increasingly wild mythology of heroes and New Gods. There was the formal inspiration of pop art and earlier collage work. Kirby was a cultural sponge, absorbing creative influences and the turbulent social changes of the sixties.
A somewhat obscure example of Kirby's photo-collage is the sublimely strange Spirit World, with the story Children of the Flaming Wheel. This is Kirby at his most wondrously weird. This comic's uncanniness combined and it's magazine format left DC not sure how to market it, and newsstands were confused as to where to place it. At this point Kirby transcended his role as comic mythologist and jumped into cosmic shaman territory.
Much of Kirby's collage work reflected his fascination with UFO's, the occult, conspiracy theories, and whatever strangeness he picked up from the hippie zeitgeist.
It's this combinatorial creativity that is at the core of not only Kirby's collage work, but his entire artistic output. As Evanier states in his book:
Most of Jack's creations in comics were, at their core, a matter of taking unconnected concepts—notions he'd gleaned from reading or movies or just sitting and musing about humanity—and juxtaposing and/or melding them together in unlikely fusion.
Kirby's mad chemistry is a credit to his curious mind and constant engagement with his work. It's also an example of how creativity is connecting things.