At its best, Star Trek is a science fiction series about humanity's ability to expand its horizons and overcome differences. But all that would be pretty boring without some great villains to overcome. Trek's bad guys have been a mixed bag, ranging from the laughable — looking at you, Harry Mudd — to the legitimately terrifying — The Borg.
Who's the baddest of the bad? Here's TIME's ranking of the 10 best Star Trek villains ever.
The omnipresent, omnipotent, omni-jerkwad Q is up here in tenth place only because he's not really a villain — he just loves messing with the crew of Picard's Enterprise. Sure, he can be a real pain sometimes, like when he tried to tempt Commander Riker with godlike powers. But he also helped the Enterprise, and the Federation at large, by flinging the Enterprise into a confrontation with another big bad on this list — the Borg. This move gave humanity a sense of what they were up against while they were out there, boldly going.
There are few Klingons less honorable than sisters Lursa and B'Etor of the House of Duras, whose actions plunged the Empire into civil war. They also had a history of working with Romulans to take control of Klingon politics, which is the sort of thing that would get you stabbed with a Bat'leth. The Duras Sisters came close to killing Picard's crew, but some quick work by Commander Data helped the Enterprise-D turn the tables on their Bird of Prey — though the Federation flagship suffered irreparable damage in the process.
The robotic probe Nomad was launched from Earth with a noble goal: Seeking out new life and new civilizations, which is something of a theme in Star Trek. Unfortunately, a collision and melding with an alien probe turned it into a super-intelligent death machine, capable of genocide on a massive scale. But Captain James T. Kirk managed to use Nomad's grim logic against the spacecraft, leading it to self-destruct, thus saving the Enterprise, humanity and probably lots of other species. (Good job, Kirk!)
What would happen to you if you found your way to heaven, only to get torn back out? That's what happened to Dr. Tolian Soran, and it messed him up good. Soran had an encounter with "the Nexus," essentially a rift in space-time that visitors experienced as a dreamlike world they could shape to their liking. After he was pulled from the Nexus against his will, Dr. Soran became obsessed with getting back — even if it meant destroying entire worlds in the process. Not cool, dude.
Professor James Moriarty
Okay, fine, Professor James Moriarty is a pretty great villain no matter where he shows up. But he's particularly good in Star Trek: The Next Generation, where he appears as a holographic simulation that gains a degree of self-awareness and turns to evil. Eventually, Picard and crew found a clever and humane way of outsmarting him: They trapped him in a computer simulation with "enough experiences to last a lifetime." It's all very meta. Either way, Moriarty episodes are some of that series' best "Holodeck gone wrong" stories. Won't somebody fix that Holodeck?
Whereas the android Data is basically the chillest dude who ever stepped foot on the Enterprise-D, his "brother" turns out to be seriously evil. On their first encounter, Lore deactivates Data and impersonates him in an unsuccessful effort to steal the ship. Later, he attacks Federation outposts and tries to manipulate Data to get him to turn against the Enterprise crew. That almost happens, but Geordi and Captain Picard step in to remind Data his brother kinda sucks, and Data dismantles his evil twin.
The Cardassians are basically a whole species of evil jerks, with Gul Dukat among the most twisted. He oversaw the Cardassian occupation of Bajor, subjugating the planet's population as a ruthless dictator. He later aligned his people with the Dominion, an advanced government hell-bent on galactic takeover and a major Federation enemy. He ultimately ended up imprisoned in the Bajoran fire caves, which is fine, because he was not a nice person.
The Borg are Star Trek's most viscerally terrifying villain. Part organic lifeform, part machine, the Borg destroy all life they see as inferior, and assimilate any species in which they find value. They're also bound together in "the Collective," a hivemind that allows essentially zero independent thoughts or actions. And they have very powerful weapons. Picard, who was once assimilated, summed it up best in this speech:
Now here's a Klingon villain who really ranks in the top echelon of Trek baddies. After a nearby disaster put the Klingon homeworld at risk, the Federation and the Klingons moved towards peace talks — the thinking being that, if the Klingons didn't have to spend so much money on its military prowess, it could fix the planet. But General Chang, among other Klingons and Federation officials, hated to the idea of peace. Instead, they conspired to ruin the talks — only to be foiled by Captain Kirk and crew. Chang also had an annoying habit of quoting Shakespeare, so nobody really missed him.
Khan Noonien Singh
Could anybody else really take the number one spot? A genetically engineered super-human from the past, Khan was a dictator who controlled large swaths of Earth until he was nearly deposed. Instead of being captured or killed, he fled the planet on a ship in biological stasis, only to be found centuries later by Kirk and company. After Khan unsuccessfully tried to take over the Enterprise, Kirk left him to settle a nearly barren world. He was later re-discovered by another Federation ship years later, harboring intense hatred for Kirk after the planet became nearly inhospitable to life. Khan then went on a vengeance tour, nearly destroying the Enterprise with a ship-turned-suicide bomb. Thankfully, Spock saved the day — at the cost of his own life. Sorta. The takeaway is this: Khan's a seriously evil dude.