Janos Prohaska Janos Prohaska ( Hungarian : János Prohászka ) was a Hungarian stunt man , actor , and animal imitator . Several of the monsters and aliens were performed by Prohaska . Prohaska was brought into the first pilot , , by Assistant Director Robert Justman , who already had worked with him on the classic original ABC science fiction series . Justman was impressed by Prohaska ' s ability to imbue the monster costumes he wore with a " magical sense " of animation . ( ) He filmed his scenes for " The Cage " on Friday and Wednesday at Desilu Culver Stage 15 . He filmed his scenes for " The Devil in the Dark " between Monday and Thursday and on Monday at Desilu Stage 10 . He filmed his scenes for " A Private Little War " on Tuesday on location at the Bell Ranch , and his scenes for " The Savage Curtain " between Monday and Wednesday at Stage 10 . Originally , his scene with the humanoid bird for " The Cage " was to have been far more extended , but Prohaska ' s performance proved to be too weird for Director Robert Butler , who recalled . " " I remember there was some chicken – some killer fowl – being locked in some cell somewhere , and I ' m talking to this stuntman – it ' s crazy , me talking to this Janos Prohaska , [ who was ] Hungarian or something . . . [ saying ] , " Janos , okay that ' s good , baby , now try this . " And there ' s this big chicken – this killer chicken – or some equivalent . I mean , it was nuts . " " ( " " , 1st ed , p . 60 ) Needless to say , the extended scenes were not utilized in the pilot as presented . Despite having already performed in " The Cage " , Prohaska , described by Justman as a " sweet man , mild , modest and unassuming " , still had to make case - by - case pitches for additional performances in the series – as the need for outlandish creatures were few and far between , for any motion picture production for that matter – , which he did in his own peculiar fashion by becoming the creature , once inside his costume , and showing " a much darker side of his nature " , as Justman recalled , " " Janos came by our office , on spec " [ note : industry idiom for an unsolicited pitch without any guarantees ] " , and donned his chimp outfit . He scuttled around the room , suddenly sprang up onto a desk , studied his surroundings and leaped to the top of a filing cabinet . He squatted , chattering and scratching himself like Cheetah , Tarzan ' s pet ape . His performance was impressive . But when one of the secretaries walked in , Janos leaped onto her and , in hominid fashion , attempted to take uncalled - for sexual liberties . After we pried him off her , which wasn ' t easy , he apologized for " the chimp ' s " actions . " " Prohaska , aside from wearing costumes created by others – the ones he wore in " The Cage " were Wah Chang creations – , also designed and created his own , again impressing the producers when he made a pitch for one of these . Justman continued , " We made a " spec " 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 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 ) Similarly , the Mugato costume ( without its spikes and horn ) was also used by Prohaska in the " Voyage to the Bottom of the Sea " episode " Fatal Cargo " and the " Here ' s Lucy " episode " Lucy ' s Safari " . Career outside " Star Trek " . Often nicknamed " The Great Janos " , he specialized in performing different out - of - this - world creatures and exotic animals , especially apes . He was employed in numerous television series and feature films during the 1960s and early 1970s . Among others , he worked for the aforementioned " The Outer Limits " ; in particular , as already mentioned , the monster from " The Probe " , the last " Outer Limits " episode , whose movements were similar to that of the Horta . He also appeared in series such as " The Munsters " , " Lost in Space " , " Bewitched " , " I Dream of Jeannie " , " Gilligan ' s Island " , " Voyage to the Bottom of the Sea " , " The Lucy Show " , " Here ' s Lucy " ( both of which starred Desilu co - founder Lucille Ball ) and " Land of the Giants " ; and movies such as " Escape from the Planet of the Apes " ( 1971 , with Ricardo Montalban , William Windom , Jason Evers and James B . Sikking ) . His most famous – talking – role was the " Cookie Bear " , which he played on " The Andy Williams Show " between 1969 and 1971 . Prohaska ' s thick Hungarian accent prevented him from getting speaking roles . A plane crash claimed his life in 1974 , while working on the ABC series " Up from the Ape " ( aka " Primal Man " ) , which featured Anthony Zerbe . His only son , actor Robert , perished alongside his father .