Nightmare
A nightmare was an unpleasant dream which could create the emotions of fear or horror within those experiencing it.

A dreamcatcher was a component of Native American mythology, used to ward off nightmares. ()

In 1996, Highway 101 in Los Angeles was a "nightmare" to drive on in the afternoon, according to Henry Starling. ()

As a child, Spock often had nightmares, resulting in fear which his mother Amanda Grayson taught him to control by drawing. In the 2250s, the nightmares returned, prompting Spock to take leave to investigate what they might mean. ()

In the 2250s, Sylvia Tilly remarked that she would have nightmares about herself as a result of learning about her mirror universe counterpart's atrocities. ()

In 2267, Montgomery Scott referred to his substitute for a PXK pergium reactor on Janus VI as "a plumber's nightmare." ()

Later that year, Leonard McCoy wondered if Pyris VII was a result of a parallel development with Earth, as it had dungeons, curses, and skeletons, among other features. James T. Kirk replied that it was more consistent with a Human nightmare. ()

In his captain's log, Kirk noted that he found his crew's peaceful investigation of Gamma Trianguli VI to have turned into a nightmare, after Spock was injured and Hendorff was killed by pod plants. ()

Ensign  referred to his first week of active duty under Captain Blackwood of the  as a "nightmare." ()

In 2365, Deanna Troi explained to Jean-Luc Picard that a duplicate of himself from the future was seeing things in a nightmare of disjointed and half-heard voices and thus was having trouble answering Picard's questions. ()

In 2367, Captain Picard experienced nightmares following his assimilation by the Borg into Locutus, but claimed to Troi – prior to his departure to visit his hometown in La Barre, France – that they had gone away. ()

Later that year, Captain Picard asked his first officer, William T. Riker, if he had experienced any hallucinations or nightmares while the  was near the , to which Riker replied that he hadn't. ()

Also that year, Geordi La Forge awoke from a nightmare on the Enterprise, in his quarters, after being brainwashed by Romulans. ()

In 2368,  asked Data if he had ever experienced a nightmare, to which Data replied that he had never had one, since he did not require sleep. ()

Later that year, Deanna Troi fell into a deep coma after experiencing a mind rape induced by an Ullian named Jev. After awakening from it, Troi told Captain Picard that it was like waking up from a nightmare and not knowing what it was about. ()

In 2369, Julian Bashir screamed several times while trapped inside a Wadi game called Chula. Bashir later explained that he was screaming because he thought he was having a nightmare and was trying to wake himself up. ()

Later that year, Commander Benjamin Sisko urged Golin Shel-la to end the nightmare of the Ennis and the Nol-Ennis fighting and attacking each other on a moon they were all trapped on, in the Gamma Quadrant. ()

Aamin Marritza, surgically altered to appear as Gul Darhe'el, menacingly told Major Kira Nerys that he was her nemesis and her nightmare. ()

In 2370, Data told Geordi La Forge that he had experienced his first nightmare with his dreaming program. It involved a group of miners threatening Data and tearing his head off. Later nightmares had Data cut into Counselor Troi as if she were a cake and hearing Sigmund Freud's voice on a telephone telling him to "kill them before it is too late." It was later discovered that Data's nightmares were induced by interphasic organisms from Thanatos VII, which were later destroyed with an interphasic pulse. ()

Later that year, Benjamin Sisko told Arjin that field training with Curzon Dax was the nightmare of the initiate corps. ()

During a poker game with the senior staff of the Enterprise-D in 2370, Geordi La Forge tried calling Commander Riker's bluff, but found out Riker had a flush and Riker won the game. La Forge couldn't believe it, to which Riker stated, "I am your worst nightmare." ()

Jean-Luc Picard told Deanna Troi, in the middle of the night on the Enterprise-D, that his experience of moving back and forth through time was like waking up from a nightmare. ()

While in the holoprogram Julian Bashir, Secret Agent, Elim Garak referred to 20th century architecture in the 1960s setting as "another decorator's nightmare." ()

Viorsa told B'Elanna Torres that The Clown, a figure created by his species' fear, had killed two of their colleagues. When Torres asked how that was possible as nothing in their environment was real, The Clown told her it was as real as a nightmare, since he had scared the two to death, from massive heart attacks. ()

B'Elanna Torres had nightmares even one year later after she was split into two people, a Klingon and a Human, on Avery III. ()

In 2372, Worf had a nightmare in which he saw dead Klingon children and civilians on the 's bridge. Worf had this nightmare because he was accused by the Klingon Empire of murdering civilians while commanding the Defiant and was asked to be extradited. ()

In 2373, Jean-Luc Picard awoke from a nightmare about when he had been assimilated by the Borg in 2366. ()

Orum told Commander Chakotay, in 2373, that being freed from the Borg Collective by an electro-kinetic storm was like waking up from a long nightmare. ()

Later that year, Quark had a nightmare in which he saw the senior staff of Deep Space 9 walking around his bar after being killed and asking why he had killed them. Quark experienced this nightmare because he had gotten into selling illegal weapons with Hagath and his cousin . ()

In 2374, the crew of the  began to experience nightmares, all containing the same mysterious alien figure, from which they could not awaken. It was discovered that the alien was the cause of the nightmares, as he and his people were seeking revenge against the "waking species" which had harmed them all their life. The dreams ceased when Commander Chakotay threatened the aliens with destruction, forcing them to deactivate the transmitter which kept the crew of Voyager asleep. ()

Later that year, Quark, after being restored to a male from a female Ferengi, noted that the experience of it made him more compassionate, empathetic, and nurturing. Quark later said that he felt like he had been trapped in his worst nightmare. ()

In 2375, Neelix woke up from a nightmare in his quarters, due to experiencing nihiliphobia while Voyager was trapped in . ()

Later that year, after being interrogated by the Breen, both Worf and Ezri Dax experienced nightmares they regarded as terrifying. () 

In 2376, the crew of Voyager experienced "memories" of the Nakan massacre, due to the ship's proximity to a memorial which transmitted the experiences to the crew. It was initially thought the experiences were nightmares. ()

Later that year, Neelix had a nightmare that featured Commander Chakotay assimilated by the Borg, while Neelix, Chakotay, and Tom Paris were trapped on a Borg cube. ()

Also that year, Crewman Tal Celes claimed to Captain Kathryn Janeway that she sometimes had nightmares in which she was chased by algorithms. ()

In 3074, an EMH backup module of The Doctor, reactivated after seven hundred years, remarked to  on what a nightmare it was to see the various inaccuracies of Voyager and its crew featured in the Museum of Kyrian Heritage. ()

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de:Albtraum
Psychology
Deleted and unused material in background
Sleep