The Justice League might boast an impressive roster of heroes, but there are plenty of super villains to keep them on their toes.
From the White Martians to an alien mind-controlling starfish, no one could call them boring - and that's just scratching the surface of the League's decades-long career.
We're counting down the greatest Justice League villains ever - including some who may just surprise you.
While Starro (more about him later) was the first Justice League villain ever, appearing in the team's debut in Brave and the Bold #28, Despero has the distinction of appearing in the first issue of Justice League of America's actual title back in 1960.
With an incredibly distinctive look - fin, pink skin, third eye - Despero has challenged the Justice League and the DC Universe at large countless times, fitting right in with the pantheon of evil alien conquerors. (Even though one time he did get his mind switched with the Justice League International's innocuous robot sidekick, L-Ron.)
That third eye isn't for decoration, either - it's the focal point of his mind powers, which allow him to control others (and cheat at chess).
9. White Martians
Martian Manhunter has been a mainstay in Justice League teams for decades - which is why his fellow Martians have frequently been a shape-shifting, vulnerable-to-fire thorn in the League's side.
Unlike J'onn J'onnz, the White Martians are anything but peaceful. In Grant Morrison's very first JLA story arc, the White Martians used their shapeshifting powers to pose as the superteam Hyperclan, in a subversive attempt at world domination.
As the antagonists of the storyline that helped restore the Justice League concept and define the franchise for a new age, the White Martians might have earned their way on this list for that arc alone.
The Hyperclan appear to be returning once again in DC's Future State: Justice League title this January.
Unlike just about everyone else on this list, Prometheus doesn't have superpowers, he isn't an alien, and he isn't part of a crew of like-minded megalomaniacs.
Like Batman, he's just a dude who happens to be incredibly smart and unsettlingly crafty. But unlike Batman, instead of using his powers for good, he well, you can probably guess what he did, based on his inclusion in this list.
Created by Grant Morrison during his seminal run on JLA, Prometheus used his wiles to take down the entire League, before being unexpectedly taken down by Catwoman.
In the Justice League: Cry for Justice series, Prometheus's actions escalate to the point where Green Arrow puts him down with an arrow through the head - though he eventually returned, and even gave rise to several successors.
7. Injustice League
If the Justice League is a collective of DC's greatest superheroes, it only makes sense that the greatest villains would band together to oppose them, right?
In the tradition of the Legion of Doom from Super Friends, big-time bad guys like Lex Luthor and the Joker have frequently banded together to take on the Justice League, in both the less formally named 'Injustice Gang,' and the 'Injustice League.'
During Dwayne McDuffie's run on Justice League of America, the late writer took a similar approach to the Justice League Unlimited TV series and presented an Injustice League inclusive of just about everybody, from major players like Gorilla Grodd and Cheetah to more ancillary names like Nocturna and Manticore.
And speaking of the Legion of Doom, that villainous team finally became DC comic book canon in Scott Snyder's Justice League run, in which Luthor banded together some of the Justice League's greatest foes.
Built by the diabolical Professor Ivo, Amazo is an android with the power to mimic the abilities of his foes – a deadly proposition when you're one of the oldest arch-enemies of the Justice League, comprised of the world’s most powerful heroes.
Despite his slightly silly Silver Age name and look, Amazo is one of the League’s most consistently troublesome enemies, often taking on the whole team singlehandedly with the powers of Superman, Wonder Woman, Flash, Green Lantern, and more all rolled into one nigh-indestructible robot body.
In 'The New 52' era, Amazo was reimagined as a virus that gave those who contracted it eventually deadly superpowers, but came somewhat closer to resembling his original version when the virus embodied a human host.
5. Secret Society of Super Villains
They are one of the oldest and most iconic team of supervillains in the DCU, containing a who's who of the combined DC Rogue’s Gallery from Lex Luthor to Darkseid and more.
Originally formed by Darkseid, the Secret Society of Supervillains have stood toe-to-toe with both the original Justice Society and the modern Justice League. And in a still-rare move, these villains actually headlined their own book in the mid-1970s, which lasted for 15 issues.
A few years ago, the Secret Society of Supervillains actually briefly conquered the world (with the help of the Crime Syndicate) in Forever Evil.
Where there's a multiversal 'Crisis,' Anti-Monitor isn't hard to find.
The multiverse-destroying being from the antimatter universe literally brought about the destruction of infinite Earths, leaving only one left for two decades.
While the heroes of the Justice League usually led the way against Anti-Monitor, it's unfair to call him just a JL villain.
This is a threat that usually needs more like the entire assembled force of every hero on Earth, in space, and just about all of reality to take down. That easily gets him into the top half of this list.
Another alien conqueror (the League seems to face a lot of them), Starro makes his way this high on the list not just because he's an awesome alien mind-controlling starfish, but because he was the first villain the Justice League ever faced!
Premiering in Brave and the Bold #28, Starro attacked Happy Harbor and Rhode Island, the natural place an alien conqueror would start. Aquaman, The Flash, Green Lantern, Martian Manhunter, and Wonder Woman teamed up to take him down, though it was really the non-powered human Snapper Carr who figured out the key to his defeat.
Starro comes back to plague Earth on occasion, despite it originally seeming that the alien had been utterly destroyed. With mini-starfish used for more direct mind control, Starro has even taken over individual members of the League at times, in comic books, TV, and video games.
A recent hero turn which led to a heroic death resulted in the Justice League's newest and perhaps oddest member, Jarro, but that's a story for another day.
2. Crime Syndicate of America
In superhero comic books, the general public and the world's governments always worry – and prepare – in the event that one of their world's top superheroes turns bad. But imagine if they all turned evil? That’s the Crime Syndicate, an evil version of DC’s top heroes from an alternate Earth.
The concept of the 'evil twin' is certainly not one exclusive to comics, but it does offer a unique challenge for a team of superheroes. With the alternate-earth Crime Syndicate, the Justice League gets to see what it would be like if they were instead the world's greatest villains.
Ultraman, Owlman, Superwoman, Johnny Quick, and Power Ring may not all have the most original names, but the threats they pose to the League are very real. Other members have come and gone, also offering up doppelganger versions of famous heroes, but those five are usually the core of the villainous squad.
The Crime Syndicate invaded the Justice League's Earth a few years ago as part of Forever Evil, in which they very nearly defeated the League and conquered the world - all while fleeing the Anti-Monitor, who destroyed their home of Earth 3.
Ultimately, it all comes down to the Omega, and for Darkseid (fun with spelling!) that's a literal assessment.
With his Anti-Life Equation and Omega Beams, this alien overlord from Apokolips (more fun with spelling!) has plagued the Justice League since his first appearance in November 1970.
Darkseid is from the creative mind of Jack Kirby, as one of the New Gods from the far reaches of space. Using the Mother Box, he plagues the Justice League as a whole, or sometimes just Superman alone, and has proven to have staying power - Darkseid even winds up taking on the Legion of Superheroes, who tend to dwell a thousand years in the future.
Darkseid will make his live-action film debut in Justice League: The Snyder Cut.