OMG!!!!!!! WE GOT IT!!!!!! 
Just before we "thought" we were going to bed, we took a flashlight to the graveyard (that had been cleared of all bodies). And we found a margarita snail tipped over. Strange, I thought, because margaritas are well known to be able to right themselves compared to astreas
Then I looked further into the cave, and there was the HUGE b-worm heading right for the snail
We removed the lights and glass top, got a glass, a long plastic stirring spoon and the serving tongs. With the flashlight, a little yelling caused by the fear of this thing, the spoon and tongs, we GOT THAT SUCKER
Now, I'm almost positive it was the b-worm that was killing the snails, but we will be vigilant and continue to watch the tank over the next few days.
The b-worm is in a glass in the sink. If I get a chance tomorrow to take pics, I'll post them. OMG, I'm so freaked that we got that close to that monster to actually get it out
OMG, it's in a glass in the sink
OMG
OMG
OMG