Arachne

Arachne is a mythological monster that resembles a spider from the waist down and a woman from the waist up. She spits nets of webbing that slow down the player and reduce their jumping ability until they wear off. Some variants also have the ability to spit poison.

Origins
In Greco-Roman mythology, Arachne was a great weaver who boasted that her skill was greater than that of Athena, goddess of wisdom and strategy. Arachne refused to acknowledge that her knowledge came, in part at least, from the goddess. Offended by Arachne's arrogance, Athena set a contest between the two weavers. The goddess was so envious of the magnificent tapestry and the mortal weaver's success, and perhaps offended by the girl's choice of subjects (the loves and transgressions of the gods), that she destroyed the tapestry and loom and slashed the girl's face. Ultimately, the goddess turned Arachne into a spider.

Arachne simply means "spider" (ἀράχνη) in Greek, and the mythical Arachne's weaving abilities are a nod toward the spider's web-spinning capabilities.

Castlevania (N64) / Castlevania: Legacy of Darkness
Arachne is first introduced into the series via a memorable cutscene that takes place shortly after entering the Tunnel. After finding the lifeless body of a villager who drowned in poisonous water, the protagonist soon arrives to another river shore where they come across with what appears to be a beautiful lady taking a bath in the noxious waters. Looks can be deceiving, though, and as the lovely figure emerges from the water, she reveals her true nature: a horrifying  monster that portrays the torso of a woman from the waist up and the repulsive body of a giant tarantula from the waist down.

Arachnes come armed with tridents and know well how to use them. They spawn infinitely in certain areas and usually attack by surrounding the player whilst keeping a medium distance until they decide to engage in close combat. They keep harassing them for lengthy sections of the tunnels and frequently spit squirts of poison from the spider head's mouth.

Found at the end of the Tunnel, Queen Algenie can pull the player in with her web and drain their life immediately. She also attacks with smaller webbed creatures. After sustaining enough damage, she will start attacking with her limbs and spit poison.

Castlevania: Circle of the Moon
In Circle Of The Moon, Arachnes appear in the Catacomb along with Grizzlies once Death has been defeated. They pace back and forth and occasionally shoot spider webbings at Nathan. If they connect, his mobility will become severely compromised for a few seconds, most likely setting him ready to be punched by the bear and probably sent flying out of the room.

A stronger variant makes its return in the twelfth room of the Battle Arena in an overall more precarious situation, as three of them appear along with a trio of Succubi. Needless to say, fighting a Succubus requires that the player makes good use of their available space and being slowed down by the webbing will leave Nathan at the flying vampires' mercy.

Castlevania: Aria of Sorrow
In Aria of Sorrow, Arachnes appear in the Study. Here they wait for Soma to approach, then shoot a barrage of needles at him. If Soma attacks quickly or gets too close, Arachne will back-dash away from him. Their soul allows Soma to shoot forth a spider web.

Castlevania: Order of Ecclesia
In Order of Ecclesia, Arachnes appear in the Tymeo Mountains. They remain stationary until Shanoa approaches them, at which point they'll say: "Looks delicious!", and then proceed to attack. They can back-dash, but it's more like a back-jump. They also fire little poison spheres that cause poisoning. They also are blue and their female face is only fully visible when they turn. Upon death, an Arachne's body bursts and draws forth several spider-lings on the ground, which are actually harmless, and can be crushed easily once Shanoa steps on them.