Robert DeWayne Papenbrook was an American voice actor known for his extensive work in anime dubbing, video games, and live-action television series from the late 1970s until his death in 2006. He was born on September 18, 1955, in San Diego, California. Throughout his career, he was also credited under the names Robert D. Papenbrook and the pseudonym John Smallberries. Fellow voice actors often nicknamed him "Pappy".

Papenbrook's entry into voice acting came through discovery by filmmakers Steven Spielberg and George Lucas, which led to his first role providing the voices of the Hovito natives in the film Raiders of the Lost Ark. He became a prolific figure in the voice acting community, particularly recognized for portraying characters with deep or "gruff" voices. His career encompassed work on numerous anime series dubbed for English-language audiences, as well as significant contributions to the Power Rangers franchise and various video games.

Among his many anime roles, Papenbrook voiced the title character J in the series Heat Guy J. He also provided the voice for Kutal, and his powerful Hyper Kutal form, in the series Shinzo. In Dinozaurs: The Series, his credits included the role of Gigano Dragon. He had a notable presence in the Transformers franchise, voicing both the character Mega Octane and the combined form Ruination in Transformers: Robots in Disguise. Another of his roles was Rocky Hammerhead in the series Flint: The Time Detective.

Beyond the roles specified, Papenbrook's filmography was extensive. He was a familiar voice in the Tenchi Muyo! franchise, taking on roles such as Katsuhito Masaki and Nobuyuki Masaki across several series and movies. He contributed to the Digimon franchise, voicing characters like Daemon, Red Greymon in Digimon: The Movie, and various other roles across multiple series. His work extended to other popular anime such as Rurouni Kenshin,.hack//Sign, Wolf's Rain, and Eureka Seven.

In live-action television, Papenbrook was particularly well known for his voice work within the Power Rangers franchise, which spanned from Mighty Morphin Power Rangers to Power Rangers: Wild Force. His most notable live-action voice role was the character Rito Revolto in Mighty Morphin Power Rangers and Power Rangers Zeo. He also provided voices for various characters in related series such as Big Bad Beetleborgs, VR Troopers, and Masked Rider. His video game credits included roles in the.hack series, Resident Evil Outbreak, and Warcraft III: Reign of Chaos, among many others.

Bob Papenbrook passed away on March 17, 2006, in Los Angeles, California, at the age of 50 due to chronic lung problems. His legacy in the voice acting community continued through his son, Bryce Papenbrook, who also became a voice actor. The 2008 documentary DVD Adventures in Voice Acting was dedicated to his memory.