Dude, you catch more weird and/or screwed up fish than anybody, you ought to buy that book I mentioned, you would like it and it will give you sooooo much more info than your field guides.

Seeing as how Sac blackfish are filter feeders, who knows why it "struck" your bait. Are you sure you just didnt accidentally snag it? Listen to this on how they feed: "Sac blackfish are primarilly suspension feeders on planktonic algae and zooplankton. By opening and closing their mouths rapidly, they suck in large amounts of water containing small food items. The food material is carried to the roof of the mouth, where it is collected by mucus secreted by a palatal organ; clumps of mucus and food are then swallowed."

Yuck.