"Okja," South Korean filmmaker Bong Joon-ho's latest marvel, is one of the very best movies of the year -- it's touching and strange and thrilling in a way few films are. The film (premiering on Netflix and in select theaters this week) follows a young girl named Mija (Ahn Seo-hyun) as she attempts to rescue her best friend, Okja, who just so happens to be a giant, genetically manufactured pig. It's one of those classic, unlikely friendship tales, akin to "E.T." or "The Iron Giant," but filtered through Joon-ho's unique sensibilities, as he fearlessly melds satire, surrealism, broad comedy, and stark horror.

"Okja" is a wonderful movie, beautiful and bizarre, and without a convincing creature, it wouldn't have worked at all.

Bong has said that a sad-looking animal that he saw in Seoul in 2011 initially inspired him. Based on sketches by Bong (one he showed to Tilda Swinton got her interested in the project) then went to his go-to creature designer Jang Hee-chul (who also designed the monster from Bong's outstanding 2007 creature feature "The Host") and then to visual effects supervisor Erik-Jan De Boer (an Oscar-winner for "Life of Pi").

Comparing the process of designing the two creatures, Bong told me (through his very helpful translator, Jason), "There were a lot of iterations to the design and a lot of trial and error but the difference is whereas the Host was a monster, Okja, even though it doesn't exist in real life, has to have a sense of familiarity and a sense that you've seen portions of it in real life." Bong went on: "So we needed to create an animal that would seamlessly fit into a National Geographic Channel special and so with that we looked at combining elements of a manatee, hippo, and pig."

De Boer, armed with "mature concept designs" from Jang, just had to finesse the design in the computer. "That concept is not that different from what you have seen in the movie. So once we had the maquette, we scanned the maquette for rigging and once we had it in the virtual world we played around with the paws, the tail, the ears shape, there were more indicated lips in the original design that we smoothed out because it got too goofy and humanistic. We made it more canine."

The other big thing he and his team added was hair. "That wasn't something that Bong was necessarily asking for but I felt like it was necessary because it took some of the plastic sheen off of her and gave us more tools and opportunities to light her more interestingly." De Boer added: "It softened her up and made her more girly and more feminine."When you look at Okja in the movie, you can tell that this is a truly brilliant design, both because she looks so real, fitting into her environments seamlessly, and because you can relate to her on an emotional level, which is probably the rarest magic trick you can pull off in visual effects. I asked Bong when he knew they had gotten her right.

"It was the spring of 2015 when we were transitioning from the first draft to the second draft, there was a design that came up with Okja was so lovely and sweet," Bong said. "And we wanted to lean on it because it looked so plush and soft." (That draft, by the way, was co-authored by British writer Jon Ronson, who Bong hired because he was a big fan of the movie "Frank" that Ronson had written. Bong said of the experience: "It was incredibly enjoyable, we're on the same page with how we view humanity. Every character pathetically resides in the gray zone. There are no heroes or villains.")

Of course there had to be something on set. Something has to stand in for her and to be there for the cast to interact with. There are a lot of shots with hugging or sleeping on Okja, or Jake [Gyllenhaal, who plays a gonzo television host] grazing on the side of Okja," Bong said. (De Boer said that these moments of "tender physicality" are extremely hard to pull off in CGI.) Bong (who said his next film was a fully Korean genre movie about "very peculiar group of people") continued: "To take her place we created something called a stuffy, which was a fiberglass material that replicated the size and shape of Okja and had a puppeteer who moved Okja."

De Boer said that there were about 25 "stuffies" in all, "They were foam and shaped depending on each set-up. Sometimes it was a piece of the butt or flank or head. We had hats with Velcro ears. For each of these shots, we had a very specific solution. Sometimes these were solutions designed just for one shot."

When Okja is running around in the forest, that's a "weird hybrid solution." De Boer's animation supervisor was dressed in something that made him look like a sumo wrestler and mounted "tennis balls on his head." "For each of these tricky set-ups, all we focused on was legitimizing all the contact and really felt that Mija was trusting her weight to the pig."

Another goal for the team was to make it feel like there was really a six-ton creature in the forest (it then went to a team of animators tasked with "selling that weight" via "subtle shape changes in the feet, dynamic and harmonic motion in the skin that betray the collision that happens with the great"). To De Boer, this was one of the most important aspects of creating the character. "We could have animated the face and make Okja as cute as possible but if you don't believe that gravity is yanking all that weight down and trying to push it through the ground, I don't think anything is worth doing, because you won't believe that she's there," he said.

Later, when I asked De Boer if he used every trick in the book to bring the character to life, he said, simply, "Yep."

"Okja" is on Netflix and in select theaters now. Don't miss it.