‘Superman of the Mundane’ Colin Robinson back in ‘Shadows’ season ender

The metamorphosis is complete and Colin Robinson is back … and boring everyone to death.

Call it just another day (or night?) in Staten Island for the vampires of “What We Do in the Shadows,” who ended Season 4 Tuesday on FX crooning “Sunrise, Sunset,” the old classic from “Fiddler on the roof.”

Don’t ask … you had to be there.

In more urgent matters, Colin (Mark Proksch) returned to his adult form as an energy vampire, garbed in his familiar drab suit and glasses and nattering on about his home-improvement ideas — quite a change from the infant who exploded out of dead Colin Robinson’s stomach in the Season 3 finale.

Through the magic of the show’s special effects wizards, Proksch spent most of this season acting with his head transplanted onto the body of a child as Baby Colin, who sported an impressive head of hair while playing video games and tap-dancing (with tux and tails) in Nadja’s vampire nightclub.

In last week’s penultimate episode, Baby Colin morphed, literally overnight, into a head-banging teen bashing through the walls of the “Vampire Residence” with an ax — and, in the season finale, finding a hidden room/Colin Robinson archive (complete with a rack of depressing sweaters) that helped him morph back into his old dull self.

Or something.

“I was surprised how easily I was able to slip back into that character after spending time as his younger self — and trying to figure out all of those antics and tricks and characteristics that a young energy vampire who’s developing would have,” Proksch, 44, told The Post.

“Playing a child version [of Colin] was a fun diversion from the character, and fun to figure out and it breathed some new life into him for me — but at the end of the day it was a relief to get back into the old beige suit and be the ‘Superman of the Mundane.’”

Proksch said he spent a good chunk of this season shooting his Baby Colin scenes in front of a special effects green screen and away from his co-stars Matt Berry (Laszlo), Natasia Demetriou (Nadja), Kayvan Novak (Nandor) and Harvey Guillen (Guillermo aka “Gizmo”).

“That was really fun and interesting and new for me,” he said. “But I did miss being able to improvise freely with my castmates. We do a lot of improv on the show and my character, especially, improvises a lot because I have to go on long tangents that are really boring. At this point the writers don’t really write those out for me; I just blather on about a subject I know a little about so it seems natural.

“The issue [this season] was how would a child improvise with Laszlo or Guillermo? I couldn’t bring all of my knowledge as a 40-year-old; it would have to be something children would know. And, on top of that, it had to be structured around the dialogue they filmed, so it didn’t leave a ton of room for improvisation.

“But we were able to work around it, to some extent.”

Proksch said he “sometimes” shot his green-screen scenes in Toronto, where “Shadows” is filmed.

“The way it worked out was [that] we figured out pretty early on that it was too complicated to film a season and film my green screen at the same time,” he said. “The special effects were another production by itself, so I would come up [to Toronto] for tests and if I was needed for a scene or two and throw in a joke or what have you. Otherwise, the green-screen [filming] took place after the season was shot.”

“What We Do in the Shadows” will return for a fifth season. The comedy garnered seven Emmy nominations this year leading into the awards telecast on Sept. 12 — and the cast heads for Toronto the next day.

“The fact that it’s a niche comedy and deals with the metaphysical and supernatural … the fact that we’re still getting recognized is, I think, a testament to the writing, directing and editing of the show and everything else that goes into it,” Proksch said. “To get people to watch what’s basically ‘The Munsters’ in 2022 is no small feat.”