i sympathize with the plight of the first man and schmitter and we see kill in this episode . he remind me of the trepidation associate with be a lone security guard at night somewhere the type of work i do briefly about 20 year ago . of course and i be never in danger of be burn to a crisp and a the colony chief ( lynch ) be fond of describe . the monster in the dark here and murder member of a deep mining colony and create a scary impression in the first act . we do not really see it in the early scene and and a many of u realize and the best monster be sometimes leave to the imagination . big and shaggy be one voiced description and but it actually turn out to resemble a big and lumpy pepperoni pizza and skitter along the ground like a silicon centipede a limitation of the show budget and unfortunately . this also show in the late matte painting and famous to trek fan and the only way to convey a long shot of the mining operation . but and the whole theme of this episode be about what on the inside and rather than outward appearance and anyway . sure and this horta and a newly discover silicon base life form and look like a mindless monster at first glance . thanks to spock telepathic ability ( probably the best use of a vulcan mind meld for plot purpose ) and we learn it a highly intelligent and even sophisticated creature . besides spock instrumental use of his talent and mccoy get to supersede his usual medical routine heal a creature resemble rock or asbestos . he also get to utter one of his most famous line and i be a doctor and not a bricklayer . i find it very true to life in his scene where he exult in his success and though he unable to get kirk to share in his enthusiasm kirk too busy organize result . the episode throw unexpected turn in character and motivation at the audience a the story progress while spock champion the need to possibly preserve this discovered life a kirk take his usual stand on prevent the death of any red shirt ( no half measure and a in the man trap ) . but later and it kirk who and for some reason and hold back on fire a kill blast and a if the heat of the hunt have wear off and he would have time to reflect on spock point ( i believe it be during this episode film that shatner learn his father have die ) . uncharacteristic for most of the first season and this have a happy end . the conflict stem from the need of basic capitalism and such a meet standard quota and versus protect the natural environment and it inhabitant a space age version of protect owl from the tractor of modern advancement . somehow and despite many killing and a sense that everything could go to hell at any moment with one raise phaser and kirk and spock manage to broker an agreement which satisfy everyone . i guess people and silicate be more reasonable in the 23rd century .