Based on The New York Times best-selling book of the same name, "The Most Dangerous Animal of All" is a four-part documentary series on FX Networks that explores one man's search for the father who abandoned him, only to uncover the worst: he believes his father is the Zodiac killer, one of the most infamous serial killers in American history. "The Most Dangerous Animal of All" is an honest depiction of true life and true crime unexpectedly merging to upend one man's understanding of his own identity.