Spiders

Night Vale has "plenty of spiders".

Body Spiders

"The Night Vale Medical Board has issued a new study, indicating that you have a spider somewhere on your body at all times but especially now. The study said that further research would be needed to determine exactly where on your body the spider is. and what it's intentions are. Only that it is definitely there and that it's statistically likely to be one of the really ugly ones."

Tarantulas

"Friends, listeners; there’s a real tarantula problem here in Night Vale." In order to address concerns about increasing rates of illiteracy, unwanted pregnancy, and violent crime in the tarantula community, Animal Control started a series of after-school volunteer programs called "Teach a Spider to Read, Stop the Madness." Years later, all tarantulas in town reach "grade 40 level, which is the reading level of someone working on their third graduate degree due to not wanting to ever have to make a final decision about the direction of their life". The program is deemed a success and immediately defunded and shut down, the officials hoping that the tarantulas would teach their children to read without any external help. It's later revealed that the program raised the literacy rate among tarantulas from 2% to 99.7%. It lead to a record drop in violent crime in the tarantula community but simultaneously caused a huge rise in nonviolent crime, such as fraud, identity theft, cyberhacking, corporate espionage, and forgery.

One tarantula, named Nero and living in the Scrublands, saved Megan Wallaby when her transplanted body died. She found shelter in his burrow and fell in love with him, getting engaged and planning to move in with him.

Throat spiders

Throat spiders are either an illness or a symptom of illness which occasionally afflicts Night Vale residents. From the tone Cecil uses when speaking of it, it can be cured, is moderately unpleasant, and victims may take a long time to heal. Joel Eisenberg, Night Vale's only expert on flying dinosaurs, can't talk about the pteranodons that showed up at the PTA Meeting because he's still recovering from a bout with throat spiders that afflicted him the previous year. A few years later, Joel has been in remission for almost 5 years before receiving a diagnosis of the recurrence of throat spiders. They eat most of his esophagus and gain the ability to speak in his voice, they however don't understand human language, so Joel ends up talking gibberish. Doctor Veronica Duff performs arachnid-dectomy on Joel, rebuilding his esophagus using a part of his intestine.

When Cecil mentioned that Carlos sounded different lately, Carlos replied "I got new vocal cords." He went on to explain that "updating" your vocal cords is supposed to prevent throat spiders.

According to Kevin, throat spiders are usually treatable. Symptoms apparently include a strenuous cough; in the final phase of the condition, a muffled "pop" is heard and the spiders that had presumably been incubating in the victim's throat "[pour] over the craggy ledge that used to be a person's lower teeth."

Heart murmur spiders

Intern Rob had a heart murmur, and when he picked at it, the spiders got out. He also had blood streaming from his eyes and hit his head when he tried to lie down, but the important lesson, as Cecil says, is: "Never pick at a heart murmur!"

Espionage spiders

A vague yet menacing government agency uses stealthy, highly trained spiders for espionage purposes in Night Vale.

Wolf spiders

Wolf spider eggs are able to keep the embryos cool in desert heats and can be used as insulation.

Doing business with spiders

According to Louie Blasko, one should always honor their debts when doing business with spiders, as they neither forgive nor forget. Because of Blasko's debts they killed his favorite student, a clarinet player called Harold.