Arachnes are magical creatures crossed between a human and a spider. Not many of them are shown in the series, which may indicate that they are a rare species. An Arachne first appears in "Dragon Breath" and makes a few reappearances through Season 1. Arachnes are absent from Season 2.
Arachnes are humans from the waist up and spider from the waist down, much like Centaurs. They can wear modern clothes over their spider legs and body (like shirts and specially designed dresses and pants), but most avoid wearing shoes. The only one shown to do this hurt all of its legs at once.
Since Arachnes never take on a very large role, not much is known about their magic abilities. It is presumed that, like any other spider, they can walk on walls and ceilings. One is also shown shooting a sticky web out of its abdomen and easily jump around.
Only two Arachnes have been shown in the entire series:
The first is Veronica, a female Arachne who works at Magus Bazaar as a shop dealer. She often sells her wares to Fu Dog (mainly potion ingredients and other magical items). She was a dance partner option for Jake in "Dragon Breath" (until he saw the spider-like part of her body), appears briefly in "Keeping Shop", and entered as Miss Magical New York City for a pageant in "Eye of the Beholder". She also helps in the fight against the Dark Dragon in "Hong Kong Nights". She never appears in Season 2.The second known Arachne is Johnny Wang, apparently the best dancer of Hong Kong back in the 70s when Lao Shi was still a young man. Cocky and proud, he challenged the Chinese Dragon in a dancing contest, which he lost because his legs got tangled with his partners'. He only appears in the episode "Hong Kong Nights" in Season 1 and never appears in Season 2. It is possible that his dance partner (shown left) is also an Arachne, though she has normal looking legs and no visible thorax or abdomen.