Star Trek: The Enemy Within

Episode: "The Enemy Within"
Series: Star Trek: The Original Series
Season 1, Episode 5
Original Air Date: October 6, 1966

via Memory Alpha

"Chewing the scenery" is an expression often used to describe acting performances on the original series of Star Trek, particularly the work of leading man William Shatner.  His jerky movements, halting speech and exaggerated emotions have provided ample fuel for parody over the decades since.  Shatner's tendency towards overacting is on full display in "The Enemy Within."

Due to a transporter malfunction, Captain Kirk is split into two, separate selves: a good Kirk and a bad Kirk.  As the crew attempt to rectify the problem, working simultaneously to rescue an away team stranded on the planet below, Evil Kirk causes no end of trouble aboard the Enterprise.  He drinks.  He attacks women.  He attacks men.  (Alcoholic allegory?)  Meanwhile, Good Kirk has lost the nerve and resolve which he needs to effectively command the ship.

Shatner's performance as Evil Kirk is way over the top, exactly the sort of performance which has earned him much derision in pop culture.  However, his performance as Good Kirk is subtle and understated - in reality, a much taller order for an actor.  In these early episodes Shatner already wears the role of Kirk like an old shoe, a testament to greater skill than many have been willing to concede.

A couple of Trek culture notes:

• The transporter, as cool as it is, was also a convenient cost-saving device in early episodes.  Transporter effects were cheaper than those required for a shuttle craft, which could easily have rescued Sulu and the rest of the away team much sooner.  However, one of many things I admire about the Star Trek franchise is how the transporter - which still seems like pure magic - was always presented as imperfect technology.  Over the course of the series, things do occasionally go disastrously wrong.  Limits are essential for the plausibility of an imaginary world.

via Memory Alpha

• For the first time, an alien animal is featured.  In Trek lore, the creature is known simply as an Alfa 177 canine, named for its planet of origin.  The real dog inside the costume is uncredited.

James Doohan (Scotty) was born on March 3, 1920 in Vancouver, British Columbia.  A lieutenant in the Royal Canadian Artillery, Doohan was part of the force that stormed the beach at Normandy on D-Day.  He got his start in acting in radio dramas for the CBC.  A master of accents, he auditioned for Star Trek with several different nationality possibilities, ultimately settling on Scottish.  He named his own character after his grandfather: Montgomery Scott.

via Bonanza Boomers