Horta The Horta was a silicon - based lifeform from Janus VI . It was composed of a material similar to fibrous asbestos . Horta physiology was very different from the carbon - based norm more commonly found in the galaxy . Horta were difficult to detect with tricorder s , and were invulnerable to type 1 phaser s , though they could be injured with an adjusted type 2 phaser . They fed on rock , and thus they were nourished just by tunneling . Horta tunneled through rock like most humanoid s walked through air , moving with the aid of an extremely corrosive acid . They left perfectly round tunnels in their wake . This acid was so corrosive that it only left fragments of bone and teeth if used on a Human . Although Hortas did not evolve in an oxygen environment , they seemed able to exist in it for extended periods of time . The Horta species possessed ( as compared to carbon - based lifeform s ) an unusually long life span . Every fifty thousand year s , all of the Horta died out except for one , the so - called mother Horta , who then watched the egg s until they hatched , and mothered and protected them . Horta eggs were spherical in shape , and they seemed to mostly consist of silicon , aside from a few trace elements . They were stored in the Vault of Tomorrow in the Chamber of the Ages . It was in the midst of one of these temporary phases of extinction that the Federation colonized Janus VI in the 2210s . The mother Horta tolerated the Federation presence up until the miner s established a new , lower level in 2267 , where they first encountered Horta eggs . Thinking them nothing more than balls of useless silicon , the miners ' automated equipment destroyed thousands of them . The mother Horta defended her children by carrying out actions of sabotage and murder against the Janus VI colony . It was only when Commander Spock of the mind - melded with the mother Horta that he was able to determine that the Horta was actually an intelligent lifeform . In fact , before the discovery of the Horta , silicon - based life had been thought a fantasy by Federation scientist s . The mother Horta reached an accord with the miners , who were distressed at the destruction they had caused . The miners would leave the Horta young alone on the lower levels once they began hatching , while the Horta would use their abilities to locate and construct access passages to choice mineral deposits for the miners . Just as the " Enterprise " departed the planet , the first baby Horta hatched and began tunneling rapidly . ( ) In 2268 , when considering the possibility that the rock s on the planet they were investigating were alive , Sulu reminded Kirk of the Horta ( though not by name ) . McCoy then further reminded Sulu and Kirk that their instruments had registered the Horta as lifeforms , unlike the rocks they were surrounded by now . ( ) Information about the Horta was displayed by a computer , as an okudagram graphic , in Keiko O ' Brien ' s school room on Deep Space 9 . ( ) Appendices . Memorable quotes . " " NO KILL I " " " " I ' m a doctor , not a bricklayer ! " " Background information . The German word " Hort " ( male gender , der Hort ) means hoard ( as in hoard of treasure or supplies ) derived from Latin " hortus " , " garden " . Recently , the word ' s meaning is extended to include " all - day nursery " – a place where you " hoard " children ( hence cognate to Kinder " garten " ) , fitting after - the - fact the role the Horta had . The Horta was played by Janos Prohaska . Aside from playing the creature , Prohaska also designed and created the " suit " for the creature as Producer Robert Justman clarified , " We made a " spec " " [ note : industry idiom for an unsolicited pitch without any guarantees ] " deal with Janos . If he came up with a really great creature for a script Gene Coon was writing , we ' d rent it and hire him to play the part . Janos was back within a week ' s time with his custom - designed creature . It was a large pancake - shaped glob of gook with a thickened raised center and fringe around its circumference . It sure didn ' t look like much . As Janos took the glob out of sight to put it on , Gene Coon raised an objection " Bob , why are wasting time with this ? " Suddenly , the blob skittered around the corner , making straight for us . Then it stopped , curiously , backed away , and rotated in place . The blob gathered itself up , quivered , made a whimsical up - and - down movement , grunted , and skittered away again & nadsh ; leaving behind a large , round white " egg " . Coon was dumbfounded . He watched the creature giving birth . And when the creature suddenly turned and scurried back to nuzzle its " child " , Gene was sold . " Great ! " he exclaimed , " It ' s perfect ! Just what we need . " Then he excitedly hastened back to his office to finish writing the script . " Gene Coon ' s " The Devil in the Dark " became one of " Star Trek " s most famous episodes . And Janos Prohaska played his own creation , one of " Star Trek " s most famous creatures , the highly imaginative and custom - designed mother Horta . " ( " " , pp . 214 - 215 ) What neither Justman nor Coon had realized at the time however , was that Prohaska had actually already created the creature previously for the original ABC series " The Outer Limits " , first appearing in the final episode , and that he had only slightly modified the rubber costume with veins and the " fringe " for its " Star Trek " appearance . ( ) Titled " The Probe " ( with Peter Mark Richman ) , the " Outer Limits " episode ' s storyline was about survivors of a plane crash in the Pacific waking up to find themselves ( and their life raft ) on the floor of an alien spacecraft sent to collect terrestrial lifeforms . In this episode , broadcast in , the future Mrs . Horta was performing yeoman service as a giant cold germ threatening the hapless Earth people . ( " The World of Star Trek " , 3rd ed . , p . 74 ) According to the audio commentary for , David Wise mentions that for Kukulkan ' s zoo , " " If you were to read the original script , we had animals , various life forms from earlier episodes of the live action Star Trek . There was a tribble , a couple of tribbles in one cage , there was a Horta from " Devil in the Dark " [ sic ] in another cage , they were supposed to be reference , the various menagerie of characters who had appeared in earlier " Star Trek " s . " " A Horta was referenced in the first - draft script for " In Thy Image " – the story that gradually developed into – in which Kirk reminded Dr . McCoy , now a veterinarian , of the Horta having been " patched up " by McCoy using silicone cement . ( " " , p . 125 ) Two days before filming of the Federation Council scenes in , it was requested that one of the aliens present in the setting be a Horta ambassador . As notice of the request was given so soon before the scenes were shot , however , the creation of a Horta in time for filming was an impossibility . Thus , the Horta failed to make an appearance in the film . ( text commentary , " " DVD ) Some new CGI visual effects were created for the Horta , in the remastered edition of " The Devil in the Dark " , for the 40th anniversary of the original series . Notably , the Horta emerging / tunneling through a particular rock face , when Captain Kirk encountered the Horta mother on his own , was a combination of new and original footage . Apocrypha . Although there is no current canon reason to believe the Horta ever left Janus VI , in several novels and comic books by Diane Duane , there is a Horta crew member on the " Enterprise " , Ensign Naraht , one of the several thousand children of the Horta who appears in " The Devil in the Dark " . In particular , Naraht plays a critical role in " The Romulan Way " . According to that novel , Horta who enlist in Starfleet must be regularly spray - coated with teflon , since oxygen - based atmospheres are highly caustic to Silicon - based lifeform s . " Devil ' s Bargain " has them cooperating with the Federation mining colony Vesbius to de - stabilize an asteroid headed for the planet so the " Enterprise " can safely destroy what is left of it . Some of the Horta ask for Kirk ' s recommendation to Starfleet Academy . The book also suggests that Horta can live in the vacuum of space for a short period of time . The novel " Articles of the Federation " , by Keith R . A . DeCandido , has the Horta as members of the Federation as of 2380 and are represented by one Councilor Sanaht . Further appearances include the Greg Cox and John Gregory Betancourt ' s DS9 novel , " Devil in the Sky " . Hortas were also mentioned in " The Lost Years " . In the TNG novel " Dyson Sphere " , it is revealed that Starfleet has starships crewed entirely by Horta . These ships are of standard design , with nearly all amenities removed , and are filled with solid stone , which the Horta can reshape as they see fit . The series of " " novels also has a male Horta character , Chwolkk , who serves as an engineer on the . In the MMORPG " Star Trek Online " , in the mission " Mine Enemy " , a Horta kills Tal Shiar officers and burns the words " NO KILL I , NO KILL I " into a cave floor with acid . If the player observes this , he or she will get the accolade : NO KILL I . The mission reward is a Horta hatchling pet that follows the player when activated from the inventory . Horta are also seen being employed for mining operations ; as a player ' s fleet Dilithium mine has Horta miners working in environments hostile to humanoid lifeforms . There you can also purchase Horta duty officers for your ship . Also , during the numerous anniversary events , a Horta is one of many creatures that players could be temporarily turned into by the visiting Q should they annoy him . Or just by asking if he really is that powerful . The short story " Guardians " from " Strange New Worlds VII " featured a number of Horta being relocated to the Guardian of Forever ' s planet to protect it from races or beings who might seek to abuse its powers . " Devil ' s Bargain " provides some insight into Horta culture . The mother Horta is referred to as the All Mother . In addition , Horta belong to clans based on their abilities and roles . Horta names are descriptive of the individual ' s strengths , abilities , or sometimes bestowed on them by others . In the TOS novel " The Latter Fire " , the Horta ' s taxonomic name is given as " Janus hominidae " .