Light Yagami, the student at the center of Death Note, adopts the name Kira as he uses the Death Note to punish criminals, and his increasingly unhinged laughter became one of the series' most recognizable sounds. The anime adaptation, which aired in Japan in 2006, gave that laugh its full, escalating delivery, and clips of it spread through anime edits, reaction videos and meme compilations. It remains popular because it instantly marks a character as brilliant, dangerous and dangerously pleased with themselves.