When a writer needs to think up some great, imposing force to pit against their protagonist, sometimes they go a little overboard. Yeah, it's great to see some young farmboy find the strength within needed to lead a rebellion against an evil, galactic empire, but most times, the troops fighting alongside the protagonist don't have magic space powers (we're looking at you, Luke).
And yet anyone who's never seen the show will still think they're just silly little robots...
The Daleks (Doctor Who)
At first glance, the Daleks are kind of silly. A rolling pepper shaker with two sticks for arms might not seem imposing — until you realize they're almost impossible to kill inside their shells.
Fighting a near-undying force that's backed by a ridiculous amount of troops hellbent on your extermination isn't ideal — it doesn't matter that you could just put a hat over their eyestalk.
Yep. And the other villains in the game try to capture these things — doesn't work like that.
The Reapers (Mass Effect)
Normally, giant, spacefaring warships are hard to kill. They're even harder to kill if they're sentient and are capable indoctrinating entire galaxies under their control.
Reapers are massive beings often confused with space ships. They dominate entire star systems by slowly brainwashing their inhabitants. Or, if that takes too long and they just need some troops fast, they can shoot out robot appendages to turn anyone fighting them into lifeless, obedient husks. Every conquered world joins their ranks, becoming a new enemy that our heroes must fight physically and psychologically.
A rocket launcher may be overkill, but you don't want to take any chances.
The Flood (Halo)
What's worse than fighting zombies? Fighting space zombies. One of the most deadly things about the Flood is that they can destroy their enemies with a single touch.
They cover battlefields in disease, meaning any step may lead to infection. The Flood is so terrifying that it takes two great armies, the humans and the Covenant, to band together and defeat them.
Poor bug. No one ever takes them seriously.
The Arachnid (Starship Troopers)
No good military satire is complete without an insane enemy that comes in insane numbers and is armed with insane psychic abilities.One of the most deadly things about the Arachnids was how mindless they seem. Everyone who initially thought, "oh, just a giant bug" was in for a rude awakening when they discovered they can communicate telepathically and shoot down spaceships in orbit.
The Borg even managed to assimilate the great Captain Jean-Luc Picard. And adding Picard to their ranks definitely gives them an edge.
The Borg (Star Trek)
These guys are the culmination of all the terrifying things on this list. Put together highly advanced technology, overwhelming numbers, near invulnerability, and mass assimilation and you end up with the Borg.
With most sci-fi hiveminds, destroying their leader usually means the destruction of their entire force. But with the Borg, it just means another Queen must take their place.
Who would win: 40 millenia of technological advancements or one Orky boy?
The Orks (Warhammer 40k)
To be fair, every army in Warhammer 40k is a force to be reckoned with. But even in a universe filled with futuristic demons, robot zombies, and blood-thirsty elves, the Orks are considered the most successful intergalactic conquerors.
When the space savages aren't fighting among themselves, they'll band together to overwhelm their foes — even if those foes are Chaos gods, alien samurai, or whatever the hell Tyranids are.