Rockslugs can only be successfully killed with a bag of salt (which is used up) or salt shaker when their life points drop to 1-240. Fortunately, bags of salt stack, and are plentiful in the slayer master shop and in the GE. If the bag of salt is accidentally used before the rockslug is reduced to 240 or less life points, it will still be used up but have no effect. It would be wise to bring a few extra because of this. If a rockslug's health is reduced to 1 but a bag of salt is not used on it, the rockslug is "frozen" in place, unable to move or retaliate, even after it regains some life points.