Since it’s so recent, easily Jason Momoa in Fast X. Way, way, way too much.

Tom Robinson in "To Kill A Mockingbird"

As in worst acted?

Yeah, worst acting performance as the baddie or enemy or whatever.

I didn’t like Kenneth Branagh in Wild Wild West either. Ugh. It looked and seemed weird.

Javier Bardem in Skyfall.

I thought the first half of this movie was as good as any of the previous Bond films. It was absolutely fantastic ... and then Javier Bardem's character showed up. I don't mind the actor at all but this character was completely unconvincing as a villain, and annoying as hell. The second half was a chore to get through because of it. Still a great half-movie, though. I just stop watching now when his character's about to make his entrance.

Eric Bogosian - Under Seige 2
Timothy Olyphant - Live Free or Die Hard
Johnathan Pryce - Tomorrow Never Dies

Nuclear Man from Superman IV: The Quest for Peace

I didn't have an answer but Djariya just nailed it.

Also, Momoa fucking rocked it in FastX. The series had gotten too full of itself over the last few entries and his over the top flamboyant character was just what the series needed.

100%. My biggest issue with Momoa in Fast X was that he wasn’t in it enough.

Val Kilmer as Jim Morrison in the Doors

Tommy Lee Jones as Two Face - Batman Forever

I'd go with Crispin Glover as Andy Warhol for worst villain in The Doors movie, myself.

The fat Australian guy in Commando.

Mr Yunioshi in Breakfast at Tiffany's

Guy Pierce in Iron Man 3. Tony Stark misses meeting him on a rooftop on New Years Eve and he's suddenly murderous about that? Then takes some substance to make him breathe fire? Seriously? There's even dialogue in the movie saying how ridiculous it is.

Jared Leto’s Joker
Eisenberg's Lex Luthor

Don Niam as "Stingray" in Undefeatable. He has the permed mullet in the video above and he wasnt an actor just a martial artist. He really only has a few different facial expressions and isn't the greatest at delivering lines. The movie is a hell of a lot of fun.

Hard agree. Have no idea what OldBoy is smoking.

Benett! How the Hell are we supposed to believe this guy is Arnold's equal? I actually do like him as an actor and think he's fun in the role, but yeah physically he was a big meh.

I guess at least Leto's Joker wasn't the main villain in that movie (though it doesn't say much when I can barely remember what the real villain looks like besides he's a demon of some sort)

I mean this was still a step up from the villain in Superman 3...

Mamoa was fucking great in Fast X.

Bennett in "Commando"

I may have told this story before, but one time I was at a Red Sox game and some dude walked by my section dressed exactly like Bennett. Chain mail shirt, chain around his neck, moustache. It was perfect. I had to do a double take because it didn't really hit me until he had already passed by. It wasn't Halloween or "dress like an 80's villain" day at the stadium or anything. It was just totally random. I laughed so hard. My wife had no clue what I was going on about.

No, he's still terrible. Laughably bad.