Patty/Cathy The only question is which one was more evil.
Kate Bosworth/Patricia Bosworth, played by Bette Davis in A Stolen Life
Phoebe and Ursula on Friends.
And to add to my original post suggestion about “Time-Lord/Human Doctor”, here’s a probably-not comprehensive rundown on evil twin lookalikes from the original “Doctor Who” series.
Doctor #1 - the Abbot of Amboise (“the Massacre of St. Bartholomew’s”)
Doctor #2 - Salamander (“the Enemy of the World”)
Doctor #4 - android doppleganger (“the Android Invasion”)
Sarah-Jane Smith - android doppleganger (“the Android Invasion”)
Harry Sullivan - android doppleganger (“the Android Invasion”)
Sgt. Benton - android doppleganger (“the Android Invasion”)
Romana #1 - Princess Strella (“Androids of Tara”)*
Romana #2 - Princess Astra (“the Armaggeddon Factor”)*
Nyssa of Traken - Anne Talbot (“Black Orchid”)*
Doctor #5 - Omega (“Arc of Infinity”)
the Master #3 - Kamelion (“the King’s Demons” and “Planet of Fire”)*
*Not actually “evil” twins, but causing a fair amount of trouble for the good Doc. And since Romana copied her looks from Princess Astra, a case could be made that she’s the ‘evil twin.’ (because stealing somebody’s identity is just plain wrong.)
I don’t think the Human Doctor, as presented in the finale of the last series, counts as an evil twin. The Doctor, himself, describes him as much like the regular Doctor was when he met Rose - very angry, deeply steeped in hostility, but not evil.
On the other hand… spoiler for Doctor Who: The Forgotten (currently running comic series)… As of the last issue of The Forgotten, he’s trying to kill the Doctor and steal his regenerations… But, who knows if it’s actually him…the whole series has been a bit of a mindfuck…the ‘Martha’ who’s been with the Doctor the whole series was just revealed to be a projection created by the TARDIS.
And, with your username, I can’t believe you forgot Superman/Bizarro!
Or Superman/Ultraman.
Or Lex Luthor/Alexander Luthor, sr.
Or Earth-3 as a whole…
For that matter, there’s Superman/Overman (Earth-10’s Nazi version)…
Xena: Warrior Princess had plenty. Xena herself had at least three aparently unrelated living look-alikes, but none were evil. However, in the early episode Dreamworker Xena entered a dream realm and had to fight an evil version of herself representing her dark past.
Xena’s sidekick Gabrielle had an evil half-demon daughter (even stupider than it sounds) who grew up rapidly to look exactly like her in Seasons 3/4.
One of the supporting characters, Joxer, turned out to be one of a set of identical triplets. One of his brothers was a ruthless assassin. The other was a harmless and rather flamboyant musician, basically the Liberace of Ancient Greece.
In case that wasn’t enough, the Season 5 episode “Purity” had Xena encounter the twin daughters of an old friend. Unsurprisingly, one girl was good and the other was evil. That same season there was another episode involving mythical twins Castor and Pollux and their exclusive twin club, but I don’t think there were any good/evil twins involved.
The Simpsons, Treehouse of Horrors 7. Bart has a conjoined twin (they were separated in infancy) and the twin, Hugo, was locked in the attic since he was the ‘evil twin’. Of course Bart was the actual evil twin all along.
My personal favorite, The Other, from a novel written by (who would have guessed) Tom Tryon.
Short synopsis: two twin boys play around the farm. One of them is a bit more mischievous than the other.
Roddy
The Dukes of Hazzard had Jefferson Davis Hogg’s twin brother Abraham Lincoln Hogg. He dressed in all black and was quite generous snd honest.
Except for “Shoot us both, Spock!”
Don’t forget Angel/Angelus - the fact that they shared as body didn’t prevent them from being evil twins, of a sort. After all, they did find a way to fight each other.
One is a bit more DEAD than the other
From Chip & Dale’s Rescue Rangers, Gadget Hackwrench had an evil double, in a Hawaiian Islands setting. Can’t recall her name.
Zathrus in Babylon 5.
Martin/Philip in V: the Series.
That’s Zathras with an “a”, actually. I know because that’s my cat’s name.
Minor hijack: Don’t name your cat after someone who has multiple identical siblings or whatever the Zathrases are. You will end up watching a cat who looks just like yours running from the house towards almost certain doom in the form of that damned fearless coyote, freak out, try to figure out how he got outside, and find your cat sleeping peacefully in a chair. And it was raining outside so you know he didn’t just get in while you weren’t looking because he’s bone dry.
There was Good Ash / Bad Ash in Army of Darkness, and Thaddeus Ghostal and his sociopath twin brother Chad Ghostal on Space Ghost Coast to Coast. But it’s hard to call either one of the Ghostal brothers good.
Yes, and thank you for the spoiler box. I didn’t even want to take that chance of giving away the plot if someone were moved to look up this film and watch it.
Ta
Roddy
Professor X/Cassandra Nova
Superman/Bizarro
Flash (Barry Allen)/Cobalt Blue
Impulse/Inertia
Superboy (Connor Kent)/Match
Gilligan had an evil twin. I believe he was a deep cover, surgically modified, Russian Spy.
I think there was an evil doctor and a millionaire too. What about Scooby and Shaggy, think they had evil twins. Maybe Capt. Caveman and Scrappy Doo, too.
Lost in Space had an evil John Robinson in one episode.
Add in:
The entire payroll of UNIT (“Inferno” from the Pertwee era)
Also Red Dwarf had an “evil twin” episode (it’s such a cliche - how could they not?) where the ship splits into its “good” and “bad” halves.
And who could forget Arnold and Ace Rimmer? (possibly the only occasion I can think of where it’s the evil twin who’s the regular cast member)