He’s more ruthless than Logan Roy!

A subway menace with an uncanny resemblance to “Succession” star Brian Cox threatened a fellow straphanger with a gun after the pair traded insults over mothers and penis size, cops and the victim said Wednesday.

Christopher Sallas, 20, was baffled to be accosted by the doppelganger of the Scottish thespian while heading home from a concert on a Q train late last month — and told The Post that he saw the resemblance.

“Yeah, it was kind of funny in the moment. Like I said, after everything happened, after your adrenaline calms down, that’s when you get to think about the situation and see what happened,” he said.

The elderly train bully could serve as stunt double for 79-year-old Cox — complete with the same white goatee — who played a cut-throat media mogul on the hit HBO series, surveillance footage shows.

The gun-toting brute allegedly flipped out after Sallas warned him that he was feeling queasy and might want to steer clear the night of April 26.

“He got upset. I don’t know why. He just got upset and was like, ‘Oh, I don’t give a f–k if you have to throw up,'” Sallas said.

Sallas, who was nauseous from motion sickness and too much food and drink,  snapped back, “You don’t have to be f–king rude!” 

The comment infuriated the armed lookalike — prompting him to taunt Sallas by yelling that he has “a little d–k.” 

 “Oh yeah, the same one that does your mom and your girl,”  Sallas shot back.

The suspect turned out to be as touchy about his family honor as Cox’s Logan Roy character– and flew into a rage over the “momma”-type quip as the train pulled into the Jay Street station, said Sallas, who was riding home from a DDG rap concert with his girlfriend.

“He got up before the train door opened… to come towards me. I just ended up getting off the train,”  Sallas said. “So after that, I [saw] my girlfriend running, but then I turned around and he had one foot in the car and one foot out [of] the car.”

The suspect then flashed a  “small black revolver” and pointed it at Sallas before he got back on board, according to the victim and surveillance footage.

The gunman, seen wearing a hooded black coat, fled the scene, police said. 

Sallas soon realized the subway menace looked strikingly similar to the “Succession” star, who has also appeared in movies such as “Braveheart,” “Manhunter” and “Bourne Identity.”

He said he expected the decades-older commuter to be “understanding,” of his predicament – adding, “I didn’t expect that type of reaction from him.” 

“Even if it was somebody around my age, I still would have told them,” Sallas added. “No matter what, nobody wants to be next to somebody throwing up.”

“Even after I got off the train, when I started talking to the cops, I even started throwing up, like I wasn’t lying or anything,” he recalled. 

Police were seeking info about the revolver-wielding man, who had not been caught as of Wednesday.

Anyone with information on his whereabouts is asked to call the NYPD’s Crime Stoppers Hotline at 1-800-577-TIPS (8477) or, for Spanish, 1-888-57-PISTA (74782). 

The public can also submit their tips by logging onto the Crime Stoppers website at https://crimestoppers.nypdonline.org/, on X @NYPDTips.