Ethan Cutkosky as the chilling Henry Mesner is back on Law & Order: Special Victims Unit, giving Detective Amanda Rollins (Kelli Giddish) quite a fright as she attempted to celebrate a milestone with her husband, Sonny Carisi (Peter Scanavino).

While most of the criminals the squad puts away are one-and-done villains, occasionally, the squad is haunted by a particularly sick repeat offender. From sadistic serial killers to hyper-fixated psychopaths, the SVU has been forced to complete multi-takedowns on several occasions, but few could forget the horrific legacy of Henry Mesner, the 10-year-old psychopath who grew up to become the monster the detectives feared he’d one day become. Cutkosky never fails to deliver goosebumps as Henry Mesner, and he did it again on Season 27 of SVU after targeting Rollins yet again.

Giddish spoke about Rollins’ thrilling SVU reunion with Mesner during an interview with CBS, admitting that the former criminology professor remains “fascinated” with his twisted mind even all these years after ensuring his life-long prison sentence.

“[Mesner is] behind bars. He’s going to be in prison for the rest of his life. So I think that changes the dynamic there,” Giddish said while teasing the episode. “She’s already gotten him. He’s already there. And I think she’s still fascinated with how his brain works and why he does what he does, but I think she allows him in less because he’s dealing with the ramifications of his actions.”

Henry Mesner is the cat that keeps coming back on Law & Order: SVU as he continues to haunt Rollins’ narrative in Season 27’s “Career Psychopath,” where his lengthy lore with the detective stole the show. Here’s what happened.

Amanda Rollins and Henry Mesner first met year ago in SVU Season 14

Rollins first crossed paths with the sinister Henry Mesner in Season 14’s “Born Psychopath” after the squads discovered Henry’s younger sister, Ruby, was being secretly abused by her manipulative and conniving brother. Henry was just 10 years old at the time, but his sister became his way of experimenting with the sadistic as his antisocial personality disorder took hold.

Rollins was the first person to catch on to Henry’s psychopathic tendencies and urged his parents to get him help. After disregarding this warning, Henry later attacked his mother with a knife. When Rollins visited the Mesner residence, Henry made simple small talk with the detective as if nothing had happened. Henry later attempted to burn down his house with his sister inside.

When Henry’s mother revealed that her son had snapped after learning he was to be sent to a psych ward, he sent detectives on a wild pursuit after he ran away to continue with his horrific plan.

After breaking into a friend’s home, Henry stole his father’s gun and locked his friend in a closet, stealing a firearm and shooting the family’s pet dog Snowball in the process (bookmark that grim detail for later).

Henry then took a younger boy hostage at gunpoint, leading to an intense takedown after Detective Nick Amaro (Danny Pino) arrived and took him down, but not before getting shot in his bulletproof vest in the process. With that, Henry was sent to prison until he was 18 years old, and the SVU was left to wonder what kind of monster Henry would grow up to become.

Henry Mesner didn’t forget Amanda Rollins while in prison

Due to his many childhood interactions with Rollins during the dawn of his tyranny, Henry developed a fixation on the SVU detective during his time in juvenile detention. Mesner and Rollins reunited in Season 22’s “Post-Graduate Psychopath” after he was released from prison after a lengthy sentence and being “cleared” by his psychologist. Spoiler alert: Henry was a wolf lying in wait.

After Henry’s release, it didn’t take long for him to target Rollins, visiting her daughter Jesse in the park to gift her a stuffed white dog whom he’d dubbed Snowball. Upon showing the toy to her mother, Rollins’ radar went off instantly, and her worst fears were confirmed after the SVU was called in for a brutal homicide, later unveiled to be just the first step in Mesner’s long-awaited murder and rape spree.

After killing the remaining Mesners and kidnapping his sister Ruby, Rollins went through hell and high water to get Ruby back, landing in a white-knuckled hostage scenario in the process. Rollins lied to Henry and appealed to get him to let Ruby go, getting his guard down far enough that the SVU could arrest him.

During the courtroom mayhem, Henry tried to claim insanity to avoid prison, but his unbridled fury got the best of him after his attorney was interrupted by the judge. This prompted an unhinged Henry to explode in court and stab A.D.A. Sonny Carisi in the ear with a pencil, leading to his immediate evacuation from the courtroom. Due to Henry’s affinity for violence and his many transgressions, he was deemed mentally sane and sent to prison for life.

Rollins later visited a heavily sedated Henry in prison to clarify that she didn’t feel any softness for him, telling him that if he ever threatened her children or Carisi ever again, she’d kill him. Henry just smirked as Rollins left him to rot and for his strange fixation on her to fester.

Henry Mesner returned with revenge for Carisi and Rollins in SVU Season 27

Henry pulled some mind-boggling strings from prison after leveraging a fan’s obsession to get him to complete a series of horrific tasks. It all began after Rollins and Carisi celebrated their second anniversary with a romantic dinner date, only to return home to an absolute nightmare after Carisi was held at knifepoint by a masked assailant.

Rollins was able to save Carisi, but with a getaway driver prepared, the perp got away. As the SVU launched an investigation, Rollins and Carisi then started to wonder who might have had enough beef with them to target them, which is a ton of people, because they both send criminals to prison for a living.

After the assailant continued targeting high-profile individuals in the justice system, the detectives realized that all of the attacks were connected to people involved in Henry Mesner’s indefinite imprisonment. Captain Olivia Benson (Mariska Hargitay) cautioned Rollins against visiting the fixated Henry in prison, but after he refused to open up to any of the other investigators, her curiosity got the best of her.

After visiting Henry and playing mind games with him, Rollins was able to track down the contracted killer. But before she left, Henry agreed to cooperate as long as Rollins would promise to occasionally visit him, a disturbing request that Rollins pretended to acquiesce. But as the SVU arrested Henry’s puppeteer, he soon learned Rollins would never keep true to that promise.