My sides are not few.
I'm the Dodecahedron.
Who are you?"
Some creatures have a very simple shape: just a polygon or a polyhedron, such as a cube or a cone, mathematically perfect and featureless except possibly for small legs, eyes, etc.
As perfect geometric shapes can be unnerving, such beings often feel truly alien. Their perfect shape often implies that they're cold, mechanical and emotionless. That said, sometimes their appearance is simply a result of the artists being lazy.
Sometimes they may be Silicon-Based Life, while other times, they're constructed of Hard Light. Not to be mistaken with a Companion Cube (though some polyhedron-shaped Companion Cubes might be treated as if they were alive), or a Random Number God. It's not uncommon for amateur video games to feature a square or a triangle as the protagonist (and sometimes explicitly have a title along the lines of Triangle Adventures, etc.), since such heroes are very easy to draw and animate (if they're indeed animated at all).
- In Neon Genesis Evangelion the Angel Ramiel takes the form of an octahedron several hundred meters in diameter.◊ Thanks to large advances in computer technology, the creators were able to exploit and show off Ramiel's design much better in Rebuild of Evangelion. For a being that almost has a non-Euclidean design, it still has hundreds of gallons of liquid blood packed inside its core.
- Slayers: Xellos usually hides behind a fairly decent human-like disguise, but his true form is a black cone.
- The Neuroi from Strike Witches have polyhedron-shaped cores.
- Hellbound: Hellraiser II has Leviathan, the God of the Cenobites, that takes the form of a lozenge (◊).
- Bits (and Bytes) from the TRON universe are softball-sized floating polyhedrals (changing shape when the speak) that are kept as pets by the Programs. Bits can only say "yes" and "no." Bytes have a much larger vocabulary and greater intelligence.
- The Dot and the Line, inspired by Flatland, stars a dot and a line (and a squiggle).
- In H. P. Lovecraft's story "The Dreams in the Witch House", a human has to make a pilgrimage to the Cold Waste beyond the stars to where the Old Ones dwell. On the way he meets many bizarre and eldritch life-forms, polyhedra included.
- All inhabitants of Flatland are two-dimensional polygons. There's also a Sphere, which claims to inhabit a Sphereland with other 3D shapes.
- The Gods Themselves: The Rationals and Parentals that inhabit the parallel universe are ellipsoids and parallelepipeds, respectively.
- Pinwheeling four-sided sentient triangles crop up in The Light Fantastic, but these are explicable as part of a trainee Shaman's communion with the Sacred Mushrooms.
- All of the characters in Shel Silverstein's The Missing Piece and its sequel, The Missing Piece Meets the Big O. are represented as two- dimensional shapes, usually either circles, circles with wedges missing, or triangular wedges.
- The Mr. Men and Little Miss characters are all sorts of shapes, but they are all two-dimensional in illustrations. Most are circles, but Mr. Grumpy, Mr. Strong, and Mr. and Little Miss Birthday are squares, Mr. Rush, Mr. Cool, Mr. and Little Miss Christmas, and Mr. Strong's redesign in the television series are triangular, and Little Miss Sparkle is star-shaped.
- The Phantom Tollbooth has the Dodecahedron, a living geometrical solid with a hat. He only likes to use one face at a time, but each of his twelve faces expresses a different emotion; he finds it odd that Milo can live with only one.
- The Space Odyssey Series: In Arthur C. Clarke's 2010: The Year We Make Contact, the incorporeal David Bowman is led by the Monolith intelligence down through the atmosphere of Jupiter, where he sees various polyhedric kite-like creatures which feed on hydrocarbon precipitation in the atmosphere, and each other. The Monolith intelligence (with Bowman's input) assessed that these primitive nonsentients were worth sacrificing in detonating Jupiter as a second sun to help uplift the more advanced life on Europa. (Note: this was not shown in the film.)
- Pattern in The Stormlight Archive takes the form of a sentient, talkative geometric fractal.
- The creators of the Dome of Under the Dome are described as "dodecahedrons wrapped in leather" (though this may be a case of You Cannot Grasp the True Form - this takes place in visions, wherein one of them implies that it has no physical body).
- The Xipéhuz from the 1888 short story Les Xipéhuz are cone- or cylinder-shaped.
- In the Star Trek: The Original Series episode "By Any Other Name" some Redshirts get all the moisture sucked out of their bodies and turn into polyhedrons. The polyhedrons could somehow be reconstituted and are thus still alive (in some sense), but the bad guy breaks one, "killing" it.
- In The Umbrella Academy (2019), Sparrow #7, Christopher, is a living cube. No explanation for his unusual nature is given, and despite it, he's treated as just another sibling by his family.
- Dungeons & Dragons:
- Modrons from Planescape, who look like polyhedral robots. The higher in rank one is, the more sides it has. As Modrons are inhabitants of the Lawful Neutral plane of Mechanus — essentially, they're to Law what angels are to Good and demons, devils and other fiends are to Evil — their appearance fits their mechanistic, impassive nature.
- The Gelatinous Cube, a large Blob Monster shaped like a cube. Apparently, it's a life form specifically adapted for living in a typical D&D dungeon corridor.
- The Immortals ruleset for "regular" D&D includes stats for the jumper, a chronovoric creature shaped like a dodecahedron with long, slender arms on each face
- The 25th Ward hits you with one when the rotating polyhedron that serves as your interaction menu is revealed to be the current form of Kozuke Kurumizawa, the main antagonist of the game, who has been observing you all along during the game.
- Control has a benevolent being from another dimension that takes the form of a polyhedron. Because of this it's called the Hedron for short. Unfortunately, its dimension of origin also has a virulently malevolent entity, that comes to be known as the Hiss, which seeks its destruction as it is the only thing that can inoculate people against its infection.
- Cubivore: Said cubivores are cube bodies with a very large face and different rectangular prisms i.e. "flaps" that give them shape.
- Dancing Block, a Supervision game, is set in "GB (Geometric block) Kingdom in another end of the universe", and has a Mr. Dancing Block as the protagonist.
- The Doom mod The Adventures of Square. It takes place in "Shape Land" and has the protagonist, Square, face off against the evil cult "Circle of Evil" to save Doctor Octagon. According to the author, the protagonist was originally designed as "the most generic children's cartoon character possible".
- The Bomb-type enemies in Final Fantasy XIII and Final Fantasy XIII-2 are living icosahedra that start battles at half health and eventually self-destruct to deal massive damage of their respective element.
- Not featured directly in Grand Theft Auto: Vice City, but in-game adverts for "The Degenatron" talk about "save the green dots with your fantastic flying red square!" and so on, as a parody of the limitations of early 80s videogames.
- Jimmy and the Pulsating Mass: The Secret Meridian world, which represents Jimmy's struggles in school, has shapes as enemies, like the Triangle, Square, Pentagon, and Hexagon, which are literally just those shapes with eyes, or the Land Fish and its variations, which have strict geometric shapes.
- Pokémon: Porygon◊ is an artificial Pokémon which was created with a pink and blue, polyhedron-style body. Its odd shape is evidently because it was created out of "programming code".
- Polygon Man was a failed Mascot for the PlayStation in North America, meant to symbolize how many polygons the machine could render. Ken Kutaragi hated the design and Poly was quietly retired, but he eventually returned as the Final Boss of Playstation All Stars Battle Royale.
- Super Smash Bros. 64 has the Fighting Polygon Team, a series of monochrome, very low-res clones of all twelve playable characters that attacked in a Zerg Rush towards the end of arcade mode. They were replaced by higher-res mooks in later installments.
- Thomas Was Alone is an indie platformer where you control an ensemble of variously colored quadrilaterals that represent emerging AIs. While none of them speak directly, the narration ends up giving each a unique personality and voice.
- Oodle the Doodle, a triangle-shaped Living Drawing, from Animated Inanimate Battle.
- Loser from Battle for BFDI. Arguably the pentagons that scared Eraser and Pen.
- Homestar Runner: The Strong Bad Email "web comics" features a fictional Saturday morning cartoon adaptation of the fictional computer game Secret Collect. Since Secret Collect is supposedly an Atari-era game with all the characters being just large pixels, the animated adaptation makes the protagonist into an anthropomorphic cube.
- The Inexplicable Adventures of Bob! has a lengthy story involving an alien Living Ship shaped like a gigantic white cone.
- Kill Six Billion Demons: Angels' true forms tend to be very weird from the perspective of mortals and often vary a lot from one angel to the next — at least one of them is a complex, free-floating purple Euclidean solid with a halo.
- Triangle and Robert is set in a world of sapient geometric shapes; Robert is a rhombus, and Triangle is unimaginatively named. It's explicitly stated that they're only geometric shapes because the Cartoonist is incapable of drawing proper people; characters sometimes reminisce about the good old days before the strip started, when nobody was trying to draw them (and they were, implicitly, something other than simple polygons, though what they were is of course never shown, since the Cartoonist is incapable of drawing it).
- Aqua Teen Hunger Force: The episode "The Cubing" features the Wisdom Cube, a sapient and supposedly all-knowing cube from space who may just be the most obnoxious being in existence. In the end, this is revealed to actually be the Dumbassahedratron, a cousin of the real Wisdom Cube, though the genuine article is still incredibly immature.
- In-Universe: In an episode of Arthur, Sue Ellen writes a graphic novel about a country of triangles and a country of circles in conflict with each other.
- The eventual Big Bad of Gravity Falls is a maniacal, one-eyed triangle named Bill Cipher. Supplementary in-character interviews suggest his home dimension is much like what's described in Flatland, and he burned the whole place down for his own goals. When he's given a physical form he becomes a Physical God, able to warp reality at whim and assume a monstrous form as a three-dimensional, multi-armed pyramid.
- In Rubik, the Amazing Cube Rubik is a living (?) Rubik's Cube with feet sticking out the bottom and a face on one side of the cube.
- Wander over Yonder has the black cube of Darkness. While he is just a cube and not a shape with large number of sides, even the characters in the show find him strange at first, Particularly Hater and Peepers. The cube is sentient, alive and frequently displays emotion In a way…
- While viruses are on the borderline of living and non-living matter, several viruses come in the shape of polyhedra. For example, the poliovirus is an icosahedron.
- Haloquadratum walsbyi, a species of archaea with unusual square-shaped cells.