After being captured by the Initiative and implanted with a cerebral microchip which punishes him with debilitating pain whenever he harms or attempts to harm any non-demon life forms (he initially assumes it works the same with anything living), Spike turns to the Scooby Gang for protection, bartering his knowledge of the Initiative. (Though he still spars with Buffy, provided he has no real intent on harming her) His inability to bite is comically compared to impotence, much to Spike's constant humiliation; in "Doomed", he attempts to commit suicide by staking himself at Xander's house, but is stopped by Willow and Xander. Eventually, he inadvertently discovers that he can harm demons and enthusiastically joins a fight with this knowledge, showing that he's less concerned about what side he's fighting on than fighting for the thrill of it. Occasionally helping the Scooby Gang by providing them with information and/or combat assistance in exchange for cash or for the joy of fighting, but having no qualms about betraying them to such enemies as Faith and Adam. In season 4, Spike was introduced to fill the antagonistic role that Cordelia had in seasons 1 to 3; as Joss Whedon explains on the DVD featurette, "All of our characters got to the point where they were loving and hugging, and it was sort of like, where's Cordelia?" Spike appeared in every episode thereafter with the exception of "The Body".