When a band follows a promising start with a long stretch of total silence, it's not always clear whether it's fallen straight into an abyss--maybe it's just trying to let the buzz grow. Two Ton Boa, a two-bassist quartet founded by singer-songwriter Sherry Fraser, released a much lauded debut EP in 2000--Fraser's darkly intimate cabaret vocals and playfully grim narratives attracted plenty of comparisons to Polly Jean Harvey and Siouxsie Sioux, and I heard a bit of Rasputina and Jarboe in there as well. Then, nothing. Fraser says the band's disappearance was due in part to her crippling struggle with bipolar disorder, and that's borne out in the swirling unpleasantness of the group's long, long-awaited full-length,the new Parasiticide (Kill Rock Stars). Fraser toys with the new depths of abjectness a la Karen Finley even as she plays the wry narrator, and along with fellow bassist Brian Sparhawk (formerly of Fitz of Depression) she churns up dark, slimy shapes from the primordial muck. Crush Kill Destroy and the Lepers open. a 9:30 PM, Empty Bottle, 1035 N. Western, 773-276-3600 or 866-468-3401, $8.