Plutonium

Walter Hartwell "Walt" White Sr., also known by his alias Heisenberg, is a fictional character and the antihero protagonist of the American crime drama television series Breaking Bad. The character is portrayed by Bryan Cranston. Although AMC officials initially hesitated to cast Cranston due to his previous comedic role on Malcolm in the Middle, Gilligan cast him based on the actor's past performance in The X-Files episode "Drive", which Gilligan wrote. Cranston contributed greatly to the creation of his character, including Walt's backstory, personality, and physical appearance.