Metallica is just as much of a fan "Stranger Things" as the rest of the world! On Friday, the iconic heavy metal band posted a TikTok recreating the finale's tribute to their song "Master of Puppets." In their video, the scene came full circle when all four members of the band rocked out to the song alongside footage of the scene while wearing Hellfire Club shirts. Now, fans are also getting a behind-the-scenes look at how Joseph practiced for that electric scene. The writers of the show posted two clips on Twitter this weekend showing the British actor at work.