The characters in SpongeBob SquarePants were created by artist, animator and former marine biologist Stephen Hillenburg. In addition to the series' main cast, various celebrities have voiced roles in SpongeBob SquarePants. Notably, Ernest Borgnine and Tim Conway voice the roles of recurring characters Mermaid Man and Barnacle Boy respectively (Adam West assumed the role of Mermaid Man shortly after Ernest Borgnine's death in 2012), while others have taken a cameo part.