Star Trek: The Animated Series were added to the cast—claiming that Sulu and Uhura were of importance as they were proof of the ethnic diversity of the 23rd century and should not be recast. Nimoy also took this stand as a matter of principle, as he knew of the financial troubles many of his "Star Trek" co-stars were facing after cancellation of the series. Koenig was not forgotten, and later wrote an episode for the series, becoming the first "Star Trek" actor to write a "Star Trek" story. Koenig wrote "The Infinite Vulcan", which had plot elements from the original "Star Trek" episode "Space Seed"
Arena (Star Trek: The Original Series) extra Bill Blackburn in close-ups. William Shatner recalls standing too close to a stage prop explosion during the filming of the episode, causing tinnitus, which became chronic. Leonard Nimoy was also afflicted. Shatner has it in his left ear and Nimoy had it in his right ear. "Arena" was the first episode of "Star Trek" to be broadcast in color in the UK (BBC, November 1969). Zack Handlen of "The A.V. Club" gave the episode an 'A-' rating, noting the episode's influence and noting the use of a theme of "Star Trek", the "uncertainty of exploration". Arena (Star Trek: The