Cranston would trick Paul into believing his character, Jesse Pinkman, was being killed off the show.
Paul recounted an incident where Cranston hugged him and hinted at Jesse's death, leading Paul to frantically search for the script.
Cranston involved the entire crew in his pranks, including costume designers who pretended to take measurements for a casket.
Jesse Pinkman was originally intended to die in the first season, but Aaron Paul's chemistry with Bryan Cranston led to the character becoming a permanent fixture.