A spider was a type of arachnid that had eight legs and two fangs that could inject venom if present, and an unsegmented abdomen containing spinnerets that produced silk. The Arachnid Nebula was named after the spider. (ENT: "Fusion")
Captain Christopher Pike revealed he hated spiders when the USS Discovery was held in place by the Sphere's stasis field and its hold was likened to a fly being caught in a spider's web. (DIS: "An Obol for Charon")
In 2365, when Lieutenant Commanders Data and Geordi La Forge confronted a hologram of James Moriarty, he described himself as being like a spider who feels the strings vibrate when anyone new chances into his web. (TNG: "Elementary, Dear Data")
Chief Miles O'Brien was an example of someone who managed to overcome his arachnophobia. During a mission to Zayra IV, he was forced to perform a critical repair in a Jefferies tube infested with Talarian hook spiders. Afterwards, his fear had lessened to a point that by 2369, he owned a Lycosa tarantula named Christina. (TNG: "Realm of Fear")
Despite stating that spiders didn't bother him, Lieutenant Reginald Barclay was visibly uneasy when he was introduced to Miles O'Brien's pet tarantula in Ten Forward, despite O'Brien's reassurance that she wouldn't bite. (TNG: "Realm of Fear")
In 2370, when Sito Jaxa suggested that it would be good to be a "spider under the table" of the observation lounge, Sam Lavelle compared this to be a "fly on the wall". They were talking about the meeting of the senior staff in the observation lounge and were curious what they were talking about. (TNG: "Lower Decks")
Later that year, while under the influence of a T-cell stimulator, Barclay was transformed into a spider-like creature as a result of Barclay's Protomorphosis Syndrome. After the crew was cured, Deanna Troi stated that she may have to clear her calendar for the next few weeks to help him deal with the circumstances of the past few days. (TNG: "Genesis")
In 2373, after hearing Captain Kathryn Janeway's tale of her experience with the Matrix alien, Commander Chakotay compared the alien's attempt to lure her into the Matrix like being a spider that has to lure a fly into his web. (VOY: "Coda")
A species of large spider was the primary food source on a planet in a subspace pocket, accessible by a subspace sinkhole. Noss, one of many trapped on the planet, used an electronic device to attract the spiders so she could spear them. She taught the technique to Tuvok and Tom Paris when they and The Doctor also crashed on the planet in 2375. (VOY: "Gravity")
Types of spider
Several Star Trek scripts describe species, objects and technology as being spider-like:
- In the original scripts for "The Cage", the anthropoid ape is described as the "anthropoid-spider".
- A scene featured in the script for "Suddenly Human" but changed in the finished episode, describes Jono as being, "suspended from the ceiling in a spider-web hammock." 
- In the script for "Imaginary Friend", the attack on the USS Enterprise-D at the end of the episode is described as, "The ship is immersed in an astounding amount of ENERGY STRANDS – ten times as many. They surround the ship like a spider's web – tendrils draped over the ship, tangling it deeper..." 
- The remote controlled toy used by Alexander Rozhenko in "Rascals" is described in the script as being, "like a cross between a lunch-box and a spider, with several odd-looking armatures poking out from the sides." 
- The plasma storms seen on the unknown planet Jean-Luc Picard crashes on in "Liaisons" are described in the script as "large spider-like formations of PLASMA LIGHTNING." 
- The myriad of emergent circuit nodes are described as being like a "spider's web of connections" in the script for "Emergence". 
- During the scene in which the USS Rubicon is affected by a plasma storm in "Hippocratic Oath", the script describes the field as, "a SPIDER WEB of SPIKY BLUE ENERGY spreads across the front window like a net." 
- The script for "The Ship" describes the Dominion surveillance device seen in the episode as, "a spider-like DEVICE with a center body and BLINKIES extending in several directions." 
- The script for Star Trek Nemesis describes Senator Tal'aura's handheld thalaron generator as, "like a spider, standing on its legs." 
- A revised draft script for "Broken Bow" describes a hidden Suliban as being, "perched like a spider high on a WALL." 
- The noun "spider" also appears in the script for "Hatchery" which describes fetal Xindi-Insectoids as "spider-like".
The Star Trek: The Original Series novel Mutiny on the Enterprise featured the Altairian spider bird (β), a species of animal lifeform native to the Altair star system. They had the ability to fly like a bird, but were also capable of spinning webs like a spider.
The Star Trek Cookbook features the Tashmanian spider (β), a Klingon spider found on the planet Qo'noS. Considered a delicacy among Klingons, they are said to be tough enough to survive being boiled in fat.
According to the Last Unicorn Games Star Trek Roleplaying Game Among the Clans, the Glikar'ma (β), also known as the Andorian forest spider, is a large venomous arachnid found on Andoria. It also appears in the video game Star Trek Online.