This unnamed woman was an arachne and was from Greece.
Arachnes were last seen in Crete, two thousand years ago, before this one turned up in Bristol, Rhode Island. There it began attacking thirty-year old men and turning them into arachnes possibly due to Eve's influence; Sam Winchester and Samuel Campbell, hunted it, along with the help of local sheriff Roy Dobbs, however, following Sam's plan, he was captured, but the two managed to track it back to its lair, where after a fight, Sam managed to kill it by chopping its head off.
However, it had already infected its victims; thinking they were dying, Sam shot them all seeing it as an act of mercy, in his soulless state, and then burned the bodies, but by this point they were no longer human, so they survived, and once Sam was gone, they ran. Roy was one of the turned victims and he later sought vengeance against Sam but ended getting killed by him as well.