Jeff Corey Actor Jeff Corey , birth name Arthur Zwerling , played Plasus in the episode . He filmed his scenes on Tuesday and Wednesday , and between Friday and Wednesday , at Desilu Stage 9 , Stage 10 and Paramount Stage 5 . Born in Brooklyn , New York , Corey made over 200 film and television appearances in a career that spanned 61 years . His early career included appearances in such classic films as ( 1941 ) , ( 1946 ) , and ( 1947 ) . Later feature film credits include two classic western adventures released in 1969 , and . The first features " Trek " guest actors Ted Cassidy , Kenneth Mars , Don Keefer and Charles Dierkop . The latter film features one - time TOS guest actors Kim Darby , Alfred Ryder , Ron Soble , and John Fiedler . In 1948 , Corey co - starred with TOS actors DeForest Kelley and Whit Bissell in the crime thriller , which also featured Phyllis Douglas . Corey later appeared in the 1951 film , as did veteran " Trek " actor Michael Ansara . Corey also played Luke Benson , the xenophobic local shot by the mole men ' s ray gun , in the 1951 film " Superman and the Mole Men " . This movie , which also featured Billy Curtis and which was the first theatrical feature - length film featuring DC Comics ' Superman , was later edited into a two - part episode of the TV series " The Adventures of Superman " . Corey was among the many actors affected by the government ' s quest to seek out people they thought were communists . He was blacklisted in 1951 for refusing to name names of possible communists before the so - called " . " Not only did he refuse to name names , but he also critiqued the acting of previous witnesses . After being blacklisted , Corey worked as an acting teacher for twelve years , and was even one of Leonard Nimoy ' s early acting coaches . ( " Star Trek 30 Years " ) Corey returned to acting in 1963 , appearing in a drama called with Nimoy and Peter Brocco . He and Nimoy later appeared together in the 1971 film . Corey also co - starred with Salome Jens and William Wintersole in the 1966 film , which featured music by Jerry Goldsmith , and with Anthony Zerbe and Garry Walberg in , photographed by Jerry Finnerman , released in 1970 . Other films in which Corey appeared include ( 1967 , with Mary Linda Rapelye ) , ( 1970 , with Alan Oppenheimer and stunts by Hal Needham ) , ( 1970 , with James Gregory and Lou Wagner , and music by Leonard Rosenman ) , and ( 1977 , with Teri Garr , Paul Sorvino and David Ogden Stiers ) . His later career included a role in the 1984 fantasy film " Conant the Destroyer " ( alongside young Olivia d ' Abo and featuring music by Basil Poledouris ) , the 1986 TV movie opposite actresses Louise Fletcher and Alice Krige , and appearance in the 1994 films ( which featured Scott Bakula , Erick Avari and Brad Dourif ) and ( with F . Murray Abraham , Bob Minor , and " Trek " stuntman Steve Lambert ) . His television appearances include guest spots on ( " The Night of a Thousand Eyes " , with Celeste Yarnall , and " The Night of the Underground Terror " , with Nehemiah Persoff and Sabrina Scharf ) , ( " The Bridegroom " with Joanne Linville , and " A Single Pilgrim " with John Schuck ) , and ( " King of the Hill " written by John D . F . Black , and " Highest Castle , Deepest Grave " with France Nuyen and Bill Quinn ) . In 1977 , Corey , TOS star William Shatner , John de Lancie , Theodore Bikel , and Logan Ramsey appeared in the mini - series , partly directed by Leo Penn and featuring music by Gerald Fried . Corey also made two memorable appearances on the sitcom " Night Court " , appearing with John Larroquette and William Utay . In addition , Corey was the voice of the villain Silvermane in the 1990s animated series , based on characters appearing in Marvel Comics magazines . Corey died due to injuries from a fall in Santa Monica , California on 16 August 2002 , just six days after his 88th birthday . His last film was a little - known comedy called , released in 1998 and featuring " Trek " guest actors Andy Dick , Lee Arenberg , and Michael Shamus Wiles . His last television appearance came on 25 November 2000 , in " The Jackal " , an episode of which also featured Michelle Forbes and Jack Donner . He was survived by his wife of 63 years and their three children .