The final season of Netflix’s blockbuster show “Stranger Things” is kicking off today, well over nine years after the show premiered on the streaming platform. In other words, the now 21-year-old actor had to look like his 10 or 11-year-old self. According to Deadline, young actor Luke Kotokek had to stand in for Schnapp during filming. Costar Millie Bobby Brown, who plays the character Eleven, also had to undergo the same process for season four of “Stranger Things” for a similar sequence, with actor Martie Blair taking her place. While the tech isn’t exactly new in Hollywood, it’s a startling instance of de-aging tech, especially considering we’ve seen Schnapp grow up with each passing season of “Stranger Things” over the better part of the last decade.