David Harbour hosted the third episode of “Saturday Night Live’s” 45th season and wasted no time poking fun at his Netflix supernatural drama “Stranger Things.”

“SNL” cast member Pete Davidson, who had been noticeably absent for the first two episodes of the season, returned in this monologue as well.

Although at first noting that he can do other things than that show, citing his turns in Shakespeare in the Park, on Broadway and in “Hellboy” as examples, Harbour’s monologue quickly spun into a “Stranger Things” parody when he took the cameras on a walk-and-talk of the studio and immediately encountered a portal to what Kate McKinnon feared was the Upside Down. Harbour went through it and that is where he encountered Davidson.

Harbour asked if “this,” meaning the Upside Down, was where he had been so far all season.

“Yeah dude, it’s lit, right?” Davidson responded.

Davidson then asked if Harbour died at the end of the third season of “Stranger Things,” to which Harbour stammered around the answer: “I’m not exactly authorized — just watch the show, you’ll find out next season.”

In the Studio 8H Upside Down, a Demogorgon attacked Beck Bennett, and Harbour found Aidy Bryant tied to a wall.

“Barb, are you OK?” he asked. Although she corrected him, she did need help. “I won’t forget about you, Barb!” he yelled as he wandered off.

Uber-producer Lorne Michaels also appeared in the sketch, sitting at a NBC page desk and saying “everybody’s got to start somewhere.” This meant Kenan Thompson was running the show.

“I was basically running the show out there, too,” he said with a laugh.

Later in the show, Davidson also returned to the Weekend Update desk to give his take on the CDC report that sexually transmitted diseases such as syphilis and chlamydia are at an all-time high, due to dating apps.

“I don’t see the problem,” he said. “These are all things you can cure with a shot. I don’t know how this is even new, really.”

He went on to say that he understands people can be worried about STDs, but he gets “tested all of the time because I look like I have all of them and I might have created my own.” But, he continued, the ones Weekend Update co-anchor Colin Jost just mentioned can be cured quickly. “The flu can last a month, but syphilis is like four days. Bring it on,” he said.

Davidson also wanted to point out that these dating apps have helped people date outside of their race, religion and social class. “You’re going to risk all that ethnic harmony just to keep a few busted pipes from dripping? I don’t think that’s fair,” he said.

Davidson said he heard that joke and looked it up and “it was not me.

“And by the way, Colin, I don’t know if you’ve seen ‘Joker,’ but you should start being way nicer to me,” he said.

Previously this season, Jost made a Weekend Update joke about Davidson’s absence on the show when reading a news item about a man who could not remember where he parked a car a week after he drove it to a music festival. “Well, we hope you make it back, Pete,” Jost said with a smile.

Reportedly, Davidson missed the earlier episodes due to filming “Suicide Squad.” He was seen in a photo on writer and director James Gunn’s Instagram on Sept. 28, the night of the Season 45 premiere.

Watch David Harbour’s “SNL” monologue below:

Watch Pete Davidson on Weekend Update below:

“Saturday Night Live” airs live coast-to-coast Saturdays at 11:30 p.m. ET/8:30 p.m. PT on NBC.