The Arachnids were a species who the Cardassians had military encounters with at Kobixine.

The Arachnids outnumbered the Cardassians and some Cardassians were in favor of negotiating with them. Procal Dukat believed that negotiation was pointless and that the Cardassian Union should exterminate them while it had the element of surprise on its side. Gul Karn "caved in" (according to Dukat) and the Cardassian forces were slaughtered by the Arachnids. (DS9 novel: A Stitch in Time)