In which year, did this earliest guest star in 1999 for SpongeBob SquarePants stop providing the voice?
Mermaid Man and Barnacle Boy Mermaid Man and Barnacle Boy are fictional superheroes in the Nickelodeon animated television series "SpongeBob SquarePants". Mermaid Man was voiced by Ernest Borgnine from 1999 to his death in 2012, and Barnacle Boy is voiced by Tim Conway. Mermaid Man and Barnacle Boy were created and designed by Stephen Hillenburg. The characters debuted on August 21, 1999 in the series' episode "Mermaid Man and Barnacle Boy".
Mona Simpson (The Simpsons) Mona Penelope Simpson (née Olsen) is a recurring fictional character in the animated television series "The Simpsons". She has been voiced by several actresses, including Maggie Roswell, Tress MacNeille, Pamela Hayden, and most prominently, Glenn Close. Glenn Close's performances as Mona have been well received by critics and she was named one of the top 25 guest stars on the show by IGN.