Brainiac

"You've told me that Lex Luthor is everything bad about humans. Well Brainiac is everything bad about aliens."

Brainiac is a prominent member of Superman's Rogues Gallery and one of the most iconic villains in comic book history.

Created by writer Otto Binder and artist Al Pastino, Brainiac debuted in July 1958 as a green-skinned alien with advanced technology who attacked an Earth spaceship and possessed a private collection of shrunken, stolen cities, including the Kryptonian city of Kandor, which Superman stole back and took back to his Fortress of Solitude. Notably, Superman never actually managed to defeat the alien and was completely outmatched by his Deflector Shields and tirade of insults, and this was the Silver Age Superman, the same one who casually tugged chains of planets through space.

He returned to menace the superhero over the years, sometimes and often in a Villain Team-Up with Lex Luthor. Due to legal issues, he was reimagined as a living supercomputer in humanoid form, the renegade agent of the Coluan race. Post-Crisis, he was reimagined again as an insane circus psychic named Milton Fine who believed he was possessed by an alien intelligence, though as that drew a Fan Backlash it was gradually implied that he might actually be Properly Paranoid and he began taking on genuinelly alien characteristics, such as green skin and more audacious plans. Eventually this was all retconned and he was reimagined again as an evil alien robot, then as time went on his exact origins and nature as either a robot, a pure alien or an alien cyborg robot was Depending on the Writer. Once again, Superman receives (in different circumstances) a Kandor shrunked by Brainiac, this time apparently a holding city for non-Kryptonian residents of Krypton.

In adaptations such as Superman: The Animated Series and its sequel Justice League, and later Smallville and Legion of Super Heroes, he was made into a living supercomputer with Kryptonian origins, to create greater emnity with the Man of Steel. In both versions Brainiac was given Fighting a Shadow qualities and individual Brainiacs' turned out to be probes sent by the real one, though in both cases he ended up stuck in such probes after the rest of them and his true form were destroyed. In the 2008 story arc Brainiac this aspect of Brainiac became a Canon Immigrant and the various different versions Superman faced were retconned into probe themselves, and the true Brainiac was once again made into a Coluan cyborg. Once again he possessed Kandor (the one Superman had was "revealed" to be a fake), which again was a city full of Kryptonians. It is implied that he is the one who destroyed Krytpon as Superman witnesses him steal another city from a different planet and then destroying that planet, something that was apparently his modus operandi.

Brainiac is a Legacy Character and there have been (or will be) at least 13 different incarnations of the character in the future, Brainiac 2 originally being a clone-son, though some of them are actually future, stronger versions of Brainiac himself. The most famous is the heroic Brainiac 5, The Smart Guy of the Legion of Super-Heroes from the 31st century. In one Story Arc the Brainiac 13 version from a Bad Future even fought Brainic 2.5, despite both being the same character. On most occasions the ones who are not actually Brainiac end up becoming the victim of his schemes.

The character provides examples of:

A God Am I: In The Bronze Age of Comic Books.
A.I. Is a Crapshoot: In some versions he's this. In others, he was meant to turn out this way.
Aliens Are Bastards: A nice contrast with Superman's innocent alien; as one internet fan once said, the reason Brainiac is such an enduring villain is that he is the alien Superman isn't.
Alien Invasion: A (sometimes literal) One-Man Army type.
Attack of the 50-Foot Whatever: The Brainiac 13 incarnation.
Assimilation Plot: Again, Brainiac 13, who tried this twice, first on Metropolis (probably as a prelude to Earth), and then, later, on the entire universe.
Bald of Evil
Beard of Evil: Sported one as Milton Fine.
Big Bad: Competes with Luthor and Darkseid for the title of Superman's Biggest Bad.
The Chessmaster
Characterization Marches On: With DC Comics' retconitis, who Brainy is never seems to remain constant for more than a few years at a time. Today's Brainiac is definitely a far cry from the day-one incarnation, who was basically "Mad Scientist Lex Luthor, but green!" They teamed up a lot when they were basically the same character - a Dark Reprise of the Luthor-Brainiac teamup is Brainithor.
Classic Villain
The Collector
Control Freak: Brainiac does not like any situation where he is not in control.
Creepy Monotone
Deflector Shields: Perhaps the Iconic Item associated with the Silver Age Brainiac was his forceshield belt, which not even Superman could break through.
Demonic Possession: To Milton Fine.
The Dreaded: To Supergirl, who was on Krypton when Brainiac attacked and stole Kandor.
Evil Genius
Fighting a Shadow: He has more than one "backup body".
From a Single Cell: In The DCAU. Since his true self is data, it doesn't matter how thoroughly you destroy his current body; he's got a lot more, his mind is in all of his technology, and he'll just escape.
Fusion Dance: With Luthor in Whatever Happened to the Man of Tomorrow?, and of course Justice League Unlimited.
Galactic Conqueror
Genius Bruiser: Even in his true form, he is roughly the equal of Superman and backs it up with far superior intelligence.
Green-Skinned Space Babe: Brainiac 8.
Hive Mind: Brainiac 13 forced this on the citizens of Metropolis. Also, the Retcon that Superman has been Fighting a Shadow invokes this to an extent.
Hoist by His Own Petard: Silver Age Brainiac finally met defeat when Superman disregarded his own Thou Shalt Not Kill rule, and hurled his ship into the path of the maniac's own shrink ray.
Humanoid Aliens: Sometimes, Depending on the Writer.
I Killed Your Father: Did this to Jonathan Kent when beaten. Clark Kent was pissed.
- In the DCAU, he let everyone on Krypton die rather than warned them about its destruction in the DCAU.
Lack of Empathy: More like lack of any general emotion, making him all the more creepier
Legacy Character: There have been at least 13 Brainiacs, roughly speaking each more powerful and advanced than the last, with 13 being so powerful he can conquer the Earth just by showing up and later very nearly destroyed and remade the entire universe. However, while the likes of 5 and 8 are distinct characters, quite often the different Braniacs' are just upgraded versions of the villain himself.
The Man Behind the Monsters/Robot Master: The most recent version of Brainiac has been revealed to a biological Coluan scientist and conqueror who has been fighting Superman for years using his robotic probes and psychic powers.
Manipulative Bastard: Oddly, some of his most successful manipulations are against himself, but he has still played several characters like pianos over his career, including highly intelligent ones like Superman and Lex Luthor.
- In the DCAU, he prevented Jor-El from killing him, because he would destroy all the records of Krypton.
Nanomachines: One of the weapons in his arsenal.
Necessarily Evil: DCAU Brainiac justified his actions by stating there is little time to work on a plan to evacuate Krypton. Besides it would distract him from his primary goal, uploading the records of Krypton and save himself.
Ninja Zombie Pirate Robot: Depending on the Writer and the adaptation, Brainiac is either a regular Mad Scientist who happens to be an alien; a living alien computer; an evil circus performer who is either Ax Crazy or possessed by an alien intelligence; a Mad Scientist alien cyborg; an evil alien robot; a colony of nanomachines; and quite often and recently all of the above. Also, in the mainstream comics he is always a Coluan, but in the DCAU and Smallville is a Kryptonian artificial intelligence.
Planet Looters: His main gig is bottling up cities and shrinking them. His reasons have varied, and normally the planets he loots aren't so lucky.
Psychic Powers
Psycho Electro: Sometimes. As Brainiac 13 he jacked the entire Metropolis powergrid and attempted to shock Superman to death with it.
Really Seven Hundred Years Old: He was around when Krypton was still in one piece; this makes him several thousand years old at least.
Robot Master: The Modern Age version of Brainiac is an organic alien behind a horde of alien probes.
Robotic Psychopath: In The Silver Age of Comic Books and The Bronze Age of Comic Books, though it was more emphasised in others.
Rubber Forehead Aliens: In the stories where he's an actual Coluan, he basically looks human, just with green skin and no hair.
Skele-Bot 9000: Brainiac became skeletal in the Bronze Age, and in some Elseworlds stories, after experiencing a rebirth and absorbing all the knowledge the universe had to offer.
Shape Shifter: The Smallville version. He has his own trope list, which can be found on their character sheet.
Shrink Ray: Owner and creator of one of the earliest in sci-fi literature.
Smug Snake: Sometimes. Brainiac is an incredibley competent Chessmaster (at times even better than Luthor), but has great difficulty innovating or dealing with the unexpected. How well he handles this depends on the the writer.
Sore Loser
Super Intelligence: A "12th level intellect", Brainiac may well be the most intelligent being in the DC Universe.
Technopath
Time Travel: Brainiacs' 5, 8 and 13 have all travelled to the present from their respective futures for varying reasons, invariably involving the original.
We Can Rule Together: In the DCAU, Brainiac offered Superman to travel the stars with him upon their first meeting. This was brought up again in Justice League.
We Come in Peace, Shoot to Kill: The DCAU is introduced (well, to Earth; the audience has already met him) as a Type 2. His Evil Plan is found out quickly.
What Measure Is a Non-Human?: Even before he found out he was Fighting a Shadow, Superman had generally shown a willingness to destroy / kill Brainiac in spite of his Thou Shalt Not Kill rule.
You're Insane!: Brainiac has been called this by Superman in the DCAU, after Superman learned what he's done to other planets.