Ah, ok, lets seperate the two issues here, one being that the bristleworms are actually consuming a healthy animal preditor style, the other being that the bristleworm is irritating the animal with its formitable "bristles", now that I can agree on, I would imagine that if the tissue had become irritated enough to the point of actually penetrating the flesh causing a wound, the worms would indeed congrigate and feed resulting in the demise of the animal.. Sounds very logical.