Syntholis

Walter Koenig (/ˈkeɪnɪɡ/;) was an American actor and screenwriter. He began acting professionally in the mid-1960s and quickly rose to prominence for his supporting role as Ensign Pavel Chekov in Star Trek (1967–1969). He went on to reprise this role in all six original-cast Star Trek films, and Star Trek: Generations (1994). He also acted in several other series and films including Goodbye, Raggedy Ann (1971), The Questor Tapes (1974), and Babylon 5 (1993). As a screenwriter, Koenig worked on Land of the Lost (1974), Family (1976), What Really Happened to the Class of ’65? (1977) and The Powers of Matthew Star (1982), and wrote several books.

Wikipedia Article

The folks at Sid & Marty Krofft posted:

Krofft is saddened by the passing of Walter Koenig. He was more than just Ensign Pavel Andreievich Chekov on Star Trek but was one of the Sci Fi writers Marty Krofft hired after Star Trek was cancelled. He wrote the sixth “Land of the Lost” classic episode “The Stranger” where we met Enik, the Altrusan who thought the sleestak were his backward ancesters that he had evolved from, but instead found they had devolved into the primitive monsters the Marshalls were plagued by.
We will truly miss Mr. Koenig! May you rest in peace.