Billy Joe Cobra is a fun-loving, mischievous ghost and Spencer's best friend from Dude, That's My Ghost! Before he died, he was an enormously famous pop-star, and is still very popular posthumously. He cannot be seen or heard by others unless they are wearing a personal item that belonged to him before he died (such as Spencer's necklace). Billy's personality consists of both a bro-centric best friend and a stereotypical narcissistic celebrity. He tries to help Spencer with his movies and fit in more with life in Hollywood, although many of his efforts normally cause more problems. He often describes his days as a rock star, in which it is shown that he was extremely difficult to work with (showing up to a video shoot 2 days late and refusing to perform because he didn't like the camera man's jeans), loved to trash hotel rooms and wreck music video shoots, and treated his crew and staff horribly. He can also be somewhat temperamental, especially when someone insults him or his music. Nearly every one of Billy's songs involve him singing about how much he loves himself or how much everyone else loves him ("I'm Still in Love With Me", "I Am the Sunshine of My Life", "You Love Me, I Love Me More", etc.) although sometimes they are about things related to stereotypically extravagant lifestyles ("Big Yachts and Money"). Billy is extremely wealthy: possessing a custom limo, several private jets, planes, and yachts, a pet crocodile, and the large mansion that Spencer's family now live in.