This needs a stretch. (Feel free to remove when satisfied of completion.)
Casey Kasem was a well known retired American disc jockey, music historian, radio personality, and screen and voice actor of Lebanese Druze decent. He is best known as the host of the American Top 40, and for providing the voice of Shaggy Rogers from 1969–1997 and then again from 2002-2009. He is also known for doing the voice of Robin the Boy Wonder, Alexander from Josie and the Pussycats, Mark from Battle of the Planets and Cliffjumper from the original Transformers series. His on-screen credits include The Hardy Boys/Nancy Drew Mysteries, Saved by the Bell (starring Mario Lopez), and a cameo in 1984's Ghostbusters.
In 1995, being a devout vegan, Kasem detested reprising his role of Shaggy in a Burger King commercial, not only turning down the offer, but leaving the role entirely when the producers wouldn't make the character into a vegan. In the interium of his time away he was replaced by Billy West and Scott Innes. In 2002, he returned when it was decided that Shaggy would be a vegetarian; subtle references can be found in What's New, Scooby-Doo?. He continued until his retirement in 2009. He was succeeded by Matthew Lillard.
His retirement also brought an end to his radio career on July 4, 2009.
In October 2013, he was revealed to have Parkinson's disease (which he had been diagnosed with in 2007), until it was discovered he had Lewy body dementia, which is similiar to Parkinson's; this sadly removed his speech, which is what he is most remembered for. In May 2014, a court order had been made to investigate the whereabouts of Kasem after he had been removed from his nursing home in Santa Monica, California and it had been announced he was "no longer in the United States". He had been found a little while later in the Washington state. He finally passed away on June 15, 2014 at age 82.
This marks the first TV series to acknowledge which character an actor has played, in this case, Kasem as Shaggy. He and Don Messick were the only two actors to reprise the roles they originated.
This is an anthology special, where Shaggy isn't in every scene, but does play an intergral part. As a cash-in, Arabian Nights was later retitled, Scooby-Doo in Arabian Nights (and then Scooby-Doo! in Arabian Nights).
As Kasem and Frank Welker are the only two to reprise the roles they originated, they are included in the opening credits. Therefore, any additional role plays is uncredited.
