The Man Trap ( episode ) A mysterious creature stalks the " Enterprise " , murdering crew members . " ( Series Premiere / Franchise Debut ) " Summary . Teaser . The arrives at the planet M - 113 to provide supplies and routine medical exams to Doctor Robert Crater and his wife , Nancy , with whom Dr . Leonard McCoy was once romantically involved . M - 113 has been home to the Craters for five years , during which time they have conducted an archaeological survey of the planet ' s ruins . They are the only known inhabitants of the planet . Kirk , McCoy , and Crewman Darnell beam down to the planet and meet Dr . Crater and , apparently , Nancy Crater , but each of the landing party sees a different woman . McCoy , who says he is amazed at how little Nancy has changed since the last time he last saw her , sees the Nancy he knew twelve years prior . Kirk sees a woman similar to the woman McCoy sees , but more appropriately aged . Darnell sees a completely different , younger blond woman who looks exactly like someone he met before on Wrigley ' s pleasure planet . When he mentions this , Nancy doesn ' t seem to mind , but Kirk and ( especially ) McCoy find this an offensive remark and ask the crewman to step outside . Minutes later , Nancy leaves and still looks ( to Darnell ) like a beautiful blond woman , and he is lured away by this seductive version of Nancy Crater . Act One . Dr . Crater then arrives , treating Kirk and McCoy with hostility , telling Kirk that the only thing they need are salt tablets . Otherwise , he and his wife want to be left alone . Kirk debates this , insisting they must need other supplies and that regulations require that McCoy give them physicals at a yearly interval . After Crater realizes that McCoy is the same man he heard his wife mention , his demeanor takes a turn for the better . During the physical , a woman ' s scream is heard from outside . When Kirk goes to investigate , he finds Darnell dead , with Nancy standing over him . Darnell ' s face is scarred with circular marks . Nancy , appearing very distraught , claims she saw him put a poison ous plant called a borgia in his mouth , but was unable to rescue him in time . On the bridge , a bored and somewhat flirty Uhura is attempting to engage Commander Spock in conversation while he sits in the " Enterprise " s command chair . Kirk and McCoy beam back up . When the transporter room reports that one of the party is dead , Spock , who is still talking to Uhura , unemotionally responds , " " Bridge acknowledging . " " This causes Uhura to express wonder that Spock did not even ask who among the party had died , as it could have been Captain Kirk , whom Uhura notes is the closest thing he has to a friend . Aboard the " Enterprise " , McCoy determines that Darnell was not poisoned , and in fact McCoy can find nothing wrong with him at all . When McCoy recalls that Nancy looked younger to him and notes that he could have been looking at her through a romantic haze , Kirk snaps , " " How your lost love affects your vision doctor doesn ' t interest me . I ' ve lost a man . I " want " to know what killed him . " " Act Two . Later , McCoy discovers that Darnell ' s body has been completely drained of salt . Kirk , McCoy , and two crewmen beam back down to the planet to investigate further , and Kirk insists that Dr . Crater and his wife beam up to the " Enterprise " until the investigation is complete . Abruptly Dr . Crater runs off to find Nancy . Sturgeon , one of the crewmen who beamed down with Kirk and McCoy , is found dead . The other , Green , is also killed by Nancy and then " Nancy " transforms into Green . Kirk and McCoy question Nancy / Green , and then the three beam up to the " Enterprise " . The woman Kirk and McCoy saw as Nancy Crater , and later Green , is a shape - shifting creature , the last surviving native of M - 113 , and can literally appear as a different being to each person it meets . By reaching into their minds and drawing on their memories , the creature can lull potential victims into a false sense of security , and apparently hypnotize them , before killing them . Still in the image of Green , the creature follows Yeoman Janice Rand ( who is carrying a tray of food , including a salt shaker ) into a botanical laboratory where Sulu greets Green by name . " Green " says nothing , which Rand finds curious . Eventually , " Green " exits without harming anyone , revealing the deception , or getting any salt . Loose aboard the " Enterprise " , the M - 113 creature still disguised as Green , bites his knuckle nervously , an idiosyncratic gesture " Nancy " had done earlier . When Uhura appears , the creature assumes a new form , one Uhura regards with curiosity and a sense of familiarity . When " he " begins speaking in Swahili , Uhura is delighted and responds in the same language . But then her smile fades as the creature apparently causes her to " freeze " , to the point which she is unable to respond to hails for her to return to the bridge . It is only the appearance of Sulu and Rand leaving the botanical laboratory that saves Uhura from being the next victim . She comes to her senses and acknowledges through an intercom panel that she is on her way to the bridge . But soon another victim , Crewman Barnhart , is found dead by Sulu and Rand on the " Enterprise " , with the same distinctive markings on his face . Kirk now knows that whatever killed Darnell and Sturgeon on the surface has now killed again – on board the " Enterprise " . Act Three . Kirk and Spock beam down to the planet to capture Professor Crater . While Kirk tries to reason with Crater , who is armed with a laser pistol , Spock finds Green ' s body . Kirk calls up to the " Enterprise " with his communicator and orders general quarters condition three , and has Sulu begin the search for " Green " . Crater does not want to be captured and fires his laser pistol at Kirk and Spock , hitting and partially destroying one of the ancient archeological structures . Kirk and Spock set their phaser s for stun . Spock then distracts Crater and Kirk fires a red bolt from his phaser and stuns Crater . Kirk and Spock question Crater about the creature . After Kirk inquires about Nancy , Crater says that she has been dead for a year , maybe two . He also describes the M - 113 creature , comparing it to the buffalo on the planet Earth : once they covered three states , but no longer . The problem facing the M - 113 creature is the need for sodium chloride – salt . The creature will die without salt . The rest of its race died due to this shortage , and now " Nancy " is the last of her kind . Act Four . In the " Enterprise " s briefing room , Kirk holds a conference with department heads and Professor Crater . The M - 113 creature appears at this meeting as McCoy , who the creature knows is asleep in his quarters . It is during this meeting that Crater reveals that he and the last surviving creature have formed a symbiotic relationship . Crater provides the M - 113 creature with the needed salt and , in turn , the creature gives the professor companionship . . . something Crater has craved since the creature murdered his wife , the real Nancy Crater , for her salt . Crater also admits that he can recognize the creature in any guise - - but does not reveal that the creature is presently sitting right next to him , in the appearance of Dr . McCoy . When Crater refuses to assist in the capture of the creature , Spock suggests a truth serum , and the captain asks " McCoy " about it . " McCoy " reluctantly agrees , and he ( the creature ) leaves with Crater . Spock volunteers to accompany them . Finally , the creature kills Crater in sickbay and attacks Spock . Fortunately Vulcan physiology makes him an unappetizing victim for the creature ( as Spock explains to the captain from sickbay ) . Now desperate , the creature , now once again appearing as ( age - appropriate ) Nancy , returns to McCoy ' s quarters , begging him to defend it ( her ) from Kirk and Spock , who have figured out the creature ' s secret . Kirk appears , with salt tablets in one hand and a phaser in the other , and tries to convince the doctor to stand clear : this is not the real Nancy . Even when the creature overpowers Kirk , and McCoy is standing dumbstruck at the turn of events , the doctor still cannot bring himself to shoot what appears to be the woman he once loved . Spock arrives , sees Kirk in distress , and immediately urges McCoy to shoot , but the doctor refuses . After a brief but unsuccessful struggle to take the phaser away , Spock repeatedly and violently strikes " Nancy " , in an effort to convince McCoy that this is NOT Nancy . The creature , who is apparently not affected at all by Spock ' s blows , strikes the Vulcan , knocking him across the room . Then the creature reverts to what is its apparent natural form , placing its hands on Kirk ' s face . Kirk cries out , and finally , in an emotionally painful move , McCoy kills the creature with a phaser blast , saving Kirk and the " Enterprise " crew . Afterwards , the " Enterprise " departs its orbit of M - 113 . Spock notices a solemn - looking Kirk in his captain ' s chair and asks what is wrong . Kirk solemnly replies " " I was thinking about the buffalo , Mr . Spock . " " The " Enterprise " departs M - 113 . Memorable quotes . " " Go away . We don ' t want you . " " " " What you want is unimportant right now . What you will get is what is required by the book . " " " Mister Spock , sometimes I think if I hear that word frequency once more , I ' ll cry . " " " " Tell me how your planet Vulcan looks on a lazy evening when the moon is full . " " " " Vulcan has no moon , Miss Uhura . " " " " I ' m not surprised , Mister Spock . " " " " This man shouldn ' t be dead . I can ' t find anything wrong with him . According to all the tests , he should get up and just walk away from here . " " " " Message , captain . Starship Base on Corinth IV requests explanation of our delay here , sir . Base Commander Dominguez says we have supplies he urgently needs . " " " " Tell José he ' ll get his chili pepper s when we get there . Tell him they ' re prime Mexican Reds , I hand picked them myself . But he won ' t die if he goes a few more days without them . " " " " But it ' s a mystery . And I don ' t like mysteries . They give me a bellyache . And I ' ve got a beauty right now . " " " " You could learn something from Mister Spock , doctor . Stop thinking with your glands ! " " " " Why don ' t you go chase an asteroid ? " " " " Yeah , how ' d you like to have her as your own personal yeoman ? " " " " May the great bird of the galaxy bless your planet . " " " " Why do people have to call inanimate objects " she " ? " " " " You been nipping Saurian brandy or something ? " " " " What ' s the matter ? Can ' t you sleep ? " " " " No . " " " " Try taking one of those red pills you gave me last week . You ' ll sleep . " " " " Keep a tight fix on us . If we let out a yell , I want an armed party down there before the echo dies . " " " " This thing becomes wife , lover , best friend , wise man , fool , idol , slave . It isn ' t a bad life to have everyone in the universe at your beck and call ! And you win all the arguments ! " " " " Fortunately , my ancestors spawned in another ocean than yours did . My blood cells are quite different . " " " " We don ' t want you here ! We ' re happy alone ! I ' ll kill to stay alone ! You hear that , Kirk ? Or you ' ll have to kill " me " ! I don ' t care either way ! " " " " Lord , forgive me . " " " " Something wrong , captain ? " " " " I was thinking about the buffalo , Mister Spock . " " Links and references . References . 2229 ; 2254 ; 2256 ; 2261 ; 2265 ; alkaloid poison ; archaeologist ; archaeology ; asteroid ; autopsy ; bellyache ; bait ; " Bones " ; borgia plant ; botany section ; bribery ; buffalo ; Carbon Group III ; celery ; chameleon ; chili pepper ; class M planet ; communications officer ; communications console ; Corinth IV ; crewman ; cry ; dispensary ; doctor ; ; earring ; Earth ; Electrographic Analysis ; engineering ; Engineering Deck ; fang ; file photo ; flower ; frequency ; general quarters ; Gertrude ; gland ; great bird of the galaxy ; hair ; herd ; Human ; hypnotic power ; idol ; inanimate object ; incisor ; intruder alert ; landing party ; Lord ; Life Sciences Department ; logic ; love ; M - 113 ; M - 113 creatures ; match ; MD ; medic ; Medical Department ; medical tricorder ; Mexican ; mile ; military log ; moon ; muscle s ; nightshade family ; passenger pigeon ; past tense ; phaser ; physician ; pill ; " Plum " ; poison ; pound ; prairie ; professor ; record tape ; red pill ; routine medical examination ; salt ; salt depletion ; salt tablet ; sample ; Saurian brandy ; security condition three ; ship ' s surgeon ; skin mottling ; slave ; sleep ; sodium chloride ; Space Commander ; space happy ; speaker ; starship base ; Starfleet regulations ; subspace log ; Supply and Maintenance ; Swahili ; thunder ; tonsil ; tongue depressor ; tooth ; tranquilizer ; tray ; trespasser ; truth serum ; Wrigley ' s pleasure planet girl ; United States of America ; Unnamed Federation starships ( 23rd century ) ; vegetation ; ; Vulcan s ; water ; weeper ; Wrigley ' s pleasure planet Unused references . M ' Umbha , mess call