"Dr. Horrible's Sing-Along Blog" is a musical web series created by Joss Whedon, released in 2008. The story follows Dr. Horrible, an aspiring supervillain, as he navigates his ambitions, love interests, and rivalries. The series features a unique blend of comedy, drama, and music, showcasing the struggles of its characters in a lighthearted yet poignant manner. The main character, Dr. Horrible, is portrayed by Neil Patrick Harris, while Nathan Fillion plays his nemesis, Captain Hammer. The series gained a cult following for its clever writing, catchy songs, and innovative format, being one of the first successful web-based musicals.