"If there are other intelligent life forms out there, they're far more likely to look like quivering mile-wide clumps of algae than British actors with rubber prosthetics glued to their foreheads."
"Head thick and puffy, about two feet point to point, with three-inch flexible yellowish tubes projecting from each point. Slit in exact center of top probably breathing aperture. At end of each tube is spherical expansion where yellowish membrane rolls back on handling to reveal glassy, red-irised globe, evidently an eye. Five slightly longer reddish tubes start from inner angles of starfish-shaped head and end in saclike swellings of same color which, upon pressure, open to bell-shaped orifices two inches maximum diameter and lined with sharp, white tooth like projections - probably mouths. All these tubes, cilia, and points of starfish head, found folded tightly down; tubes and points clinging to bulbous neck and torso. Flexibility surprising despite vast toughness."
—At the Mountains of Madness, H.P. Lovecraft
"How blithely you use the word alien; you have no idea how alien a thing can be."
— The Dark Side of the Sun, Terry Pratchett
Alien Brain Ball: The Elders tell of a young ball much like you. He bounced three meters in the air. Then he bounced one point eight meters in the air. Then he bounced four meters in the air. Do I make myself clear?
Henry Kissenger: Mr. Ambassador, our people tell the same story.
— Futurama, "War is the H-Word"
Why except for their transparent heads, furry green eyeballs, seven legs and three lips, they looked just like you and me!
— Kremmen of the Star Corps
"Xenoids are things without bones."
— Presumed Dead, by Rick Kennett
Avon: This happens to be the most sophisticated lifeform that it has ever been my good fortune to come across. Present company not excepted.
Tarrant: Life? But it looks like...
Avon: A rock. Yes. Well, when you live on the permanent dark side of a planet, nobody cares too much what you look like.
— Blake's 7, "The Harvest Of Kairos"
"Don't let the chromatophores fool you. I exist in only three dimensions and I have a certificate saying so."
— Sam, Freefall
In the interstellar gulf, a ship dropping out of Elsewhere for repairs had discovered a paleotech - dead, at last by human terms (though Kin Arad had pointed out that paleotechs probably lived by a different time scale and that this apparently lifeless husk may have been very much alive if considered by slow, megagalactic Time). It was a thin-walled tube half a million miles long.