Redjac Redjac ( also known as Red Jack , Jack the Ripper , Beratis , and Kesla ) was a non - humanoid lifeform that existed for centuries by journeying from planet to planet and feeding on the pain and fear he caused by committing serial murder s . Spock believed that female victims were chosen more often than male ones because " women are more easily and more deeply terrified , generating more sheer horror than the male of the species . " As a non - corporeal being , which was likened to a cloud creature , its physical appearance was unknown , but it was described by Mr . Scott after a brief encounter in the dark as , " cold . . . like a stinking draft out of a slaughterhouse , but it wasn ' t really there . " It had many abilities , and could possess others and even objects , like the . It was similar to a parasitic organism , and required a humanoid host to inhabit in order to commit crimes . After Redjac committed a murder on the pleasure planet Argelius II in 2267 as " Hengist " , Lieutenant Commander Montgomery Scott from the Federation starship " Enterprise " was accused of the crime . However , Hengist ' s true identity was later revealed . In the process , Redjac briefly possessed Prefect Jaris , who was quickly liberated by a nerve pinch from Spock . Subsequently , the Redjac entity was beam ed , on a dispersal pattern , into deep space by Spock , where it was hoped that it would die from lack of nourishment . ( ) Appendices . Apocrypha . In James Blish ' s novelization of the original script , Redjac manifested itself on the viewscreen in the form of a Dante sque scene , with fire and brimstone , naked women riding on the backs of satyrs , horned toad s , etc . Kirk declared that it was a vision of Hell , whereby the " filthy thing " was showing the " Enterprise " crew where it was born . In a comic story released by WildStorm Comics titled " Embrace the Wolf " , it was revealed that Redjac survived by latching on to a nearby starship . After an absence of over a century , Redjac returned to confront the crew of the , where , having provoked a nuclear war on a Federation planet , he transferred himself into the holodeck and abducted several crewmembers , challenging Data in his Sherlock Holmes persona to save them , while Redjac manifested a body for himself in the form of a skeletal figure with glowing eyes . Data was able to save Counselor Troi from Redjac , and was also able to contact Captain Picard , Dr . Crusher , and Lt . Worf . Tricking Redjac into a confrontation with Worf , the crew was able to have Redjac focus all his energy on one spot , before trapping him in a photon torpedo . The torpedo was subsequently abandoned on a nearby barren moon . Redjac also returned in two issues of the first " Star Trek " series from DC Comics , in a two - part comic with the titles " Wolf on the Prowl " and " Wolf at the Door " . In this story , the entity possessed " Enterprise " crewperson Nancy Bryce and forced her to kill a number of ship personnel . Redjac had been revealed to have spent the twenty years between the TV episode and the comics on a primitive planet where it set itself up as their " God " and presented an image of Kirk in an opposite role as a " Devil " in the context to this " God " . Redjac was defeated by following the Excelsior into a wormhole , which was then collapsed as the ship exited , trapping Redjac inside .