Realm of Fear ( episode ) Lieutenant Barclay faces his fear of transporting , but now he thinks that he ' s being attacked by a creature inside the transporter beam . Summary . Teaser . The responds to the stricken vessel . The crew of the " Yosemite " seems to have disappeared , and due to its proximity to a plasma streamer , the only way to get there safely is by bridging the transporter systems of the two ships . As the away team prepares to beam over , Transporter Chief O ' Brien informs them that due to disturbances in the plasma field , they may be experiencing problems during transportation . When Lieutenant Barclay hears this , he becomes very nervous and refuses to transport over , rushing out of the transporter room soon after Worf , Riker and Crusher beam over one by one to the " Yosemite " . Act One . Barclay , who is experiencing some form of transporter phobia , speaks to Counselor Troi about his troubles and she introduces him to a Betazoid relaxation technique known as plexing . However , completely unconvinced and still tapping himself on the neck as he walks out the door he returns to the transporter room , preparing himself for the ride . He ' s comforted a little by O ' Brien , who tells him about his fear of spiders , which he conquered by crawling through a jefferies tube past twenty Talarian hook spider s , to repair a damaged emitter array on Zayra IV . On the " Yosemite " , there ' s no sign of survivors , yet the escape pods are in place and the transporter is functional . Dr . Crusher finds a body , ship ' s engineer Joshua Kelly . When Barclay finally materializes on the " Yosemite " , Lieutenant Commander La Forge asks him to download the ship ' s science logs . They collect fragments from a broken container and the body for further analysis . Meanwhile , Picard communicates with Admiral Hayes , who mentions Ferengi allegations of Cardassian destruction of two freighters and is concerned that , if the " Yosemite " was attacked as well , it would signal large - scale movement in the sector . The landing party then beams back to the " Enterprise " . During transport , Barclay has an awful vision of a worm - like creature swimming around in the matter stream and touching his arm . He steps off of the transporter pad nervous and shaking . Act Two . Barclay is in engineering with La Forge while they try putting the logs together . Seeing them too badly damaged , La Forge turns to the broken sample container for clues . Plagued by what he saw , however , he asks La Forge if he had ever seen anything unusual while he was being transported . La Forge says he hasn ' t . Barclay then tells La Forge of his recent experience and La Forge has the transporter undergo a full diagnostic . In the transporter room , despite the exhaustive diagnostic of all subsystems and La Forge ' s and O ' Brien ' s insistence that " " transporting really is the safest way to travel " " , Barclay marvels at the job the transporters do consistently without accidents , but also how easy they are to occur . He thinks back to his Transporter Theory classes at Starfleet Academy . The empirical evidence of only a couple accidents in the past 10 years is hard to argue with , however . Barclay brings up transporter psychosis , too , but there hasn ' t been a case of that in the past 50 years . In sickbay , Dr . Crusher examines Kelly ' s body and determines it isn ' t alive , but residual ionization causes muscular activity . The heart starts beating , so Crusher quickly tries a cardiostimulator , but the activity disappears . Then , neuro - electric activity in the cerebral cortex is detected , then gone . He breathes , then it ' s gone . Barclay goes to Ten Forward to try to relax , but then finds his left arm glowing blue like during the transporter . Something must be wrong and he leaves . Act Three . Barclay goes to his quarters , drinking lots of water and even going so far as to diagnose himself with transporter psychosis after asking the computer in his quarters for causes and symptoms from the Starfleet Medical Database . Barclay ascribes his symptoms , especially hallucinations , to his transporter psychosis but keeps quiet about it . On the observation deck , Crusher reports her findings , and they suspect that the ship ' s crew decided to beam aboard a container which exploded . La Forge and Data go to engineering to examine the container , and find the residual ionization that Dr . Crusher found on the body . Data suggests to re - create the beam - in . At the end of the conversation , Data and La Forge notice Barclay ' s preoccupation and La Forge asks him to get some rest . He also asks Counselor Troi to check on him , who then relieves him of duty temporarily when she finds him pacing the corridors and being agitated . However , while in his quarters , he finds his arm glowing again . Act Four . Barclay decides to take action and goes to the transporter room , ordering O ' Brien to transport him back and forth . He sees the creature again , and calls the senior staff to the observation deck to report what ' s been going on . Picard orders another diagnostic on the transporter system and calls for a level 3 security alert . Dr . Crusher also wants to run a micro - cellular scan on him , which does confirm the residual ionization like on the body and the sample container . Barclay is convinced re - creating the beam - in of the material will shed light , and Riker agrees . They attempt to recreate conditions on the " Yosemite " . They first take the precaution of setting up a force field around the container . A sample of the plasma streamer is beamed aboard the " Enterprise " successfully , however , while running a resonance frequency scan , it explodes , though the explosion is contained within the force field . La Forge also detects highly complex patterns of biomagnetic energy . Barclay suddenly collapses , and is taken to sickbay . Act Five . In sickbay , Dr . Crusher discovers that some of the quasi - energy microbes from the " Yosemite " have gotten into Barclay ' s bloodstream during transport back to the " Enterprise " and this is what has been causing him the symptoms . La Forge and O ' Brien decide that the transporter could be used , once proper adjustments were made , to filter the microbes from Barclay ' s body while holding him in a stasis . In the transporter room , they run the process . Once Barclay is inside the beam , he sees the creepy creatures again . In a spontaneous act of bravery , the lieutenant appears to catch one of the creatures in his arms and doesn ' t let go . When he rematerializes , we see that he has another person in his grasp , one of the " Yosemite " crew members . Barclay tells the others that there are three more crew members caught in the matter stream . He sends a security team led by Worf and Kellogg in to save the rest of the " Yosemite " crew from the transporter . Barclay explains to La Forge and the chief that while the crew of the USS " Yosemite " was trying to cleanse themselves of the quasi - energy microbes , Human patterns got trapped in the transporter which didn ' t allow them to escape . Worf and the away team return with the other three members of the " Yosemite " crew . O ' Brien meets Barclay at Ten Forward , and shows him his pet Lycosa tarantula , whom he adopted and named Christina after getting over his arachnophobia . The chief remarks that he almost stepped on her when he discovered her on Titus IV . He gets up to grab some drinks , while the tarantula crawls up Barclay ' s arm , who is nervously waiting for O ' Brien to return . . . Memorable quotes . " " I ' m sorry , I just " can ' t " do this ! " " " " I know , it sounds crazy , but . . . " " " " It ' s not crazy at all . You " are " being taken apart molecule by molecule . " " " " I ' m going to beam over there . I can do it ! " " " " See , sir ? That wasn ' t so bad , was it ? " " " " Reg , transporting really is the safest way to travel . " " " " Commander La Forge said you seemed a little nervous this morning . " " " " I ' m always nervous . Everybody knows that . " " " " Mmm . . . computer , more birds . " " ( More frustrated ) " " End stress reduction program . Water . " " " " Specify temperature . " " " " I don ' t care ! Just give me water ! " " " " Chief . " " " " Lieutenant . Glad you could make it . You know , I think this is the first time we ' ve ever spoken outside of the transporter room . " " " " Well , to be honest , I ' ve always avoided you . " " " " Why ? " " " " Because you run the transporters , and I hate the transporters . At least , I used to . " " " " Uh , chief ? " " Links and references . References . 2209 ; 2319 ; autonomic system ; away team ; biofilter ; Cardassian ; Cardassian warship ; cardiostimulator ; carotid artery ; Celsius ; cerebral cortex ; Christina ; Counselor ' s office ; Delinia II ; distortion field ; DNA ; endorphin ; epidermis ; Ferengi ; Ferengi freighter ; Heisenberg compensator ; ignorance ; Igo sector ; imaging scanner ; ionic field ; ionic interference ; Jefferies tube ; kiloquad ; Lycosa tarantula ; matter stream ; medical tricorder ; micro - cellular scan ; multi - infarct dementia ; myopia ; neurochemistry ; ; Olafson ; pattern buffer ; phased matter ; phase transition coil ; plasma streamer ; plexing ; quasi - energy microbe ; resonance frequency scan ; sample container ; Starfleet Medical Database ; stellar cartography ; systems engineer ; Talarian hook spider ; tissue sample ; Titus IV ; transporter ; transporter psychosis ; Transporter Theory ; VISOR ; ; Zayra IV