Oyster drills
Drills attack oysters by boring a hole in the oyster's shell using their hard radular (or teeth). Once the drill reaches the soft tissue of the oyster it secrets digestive enzymes into the oyster, killing it. The drill then digests the oyster meat, sucking up the digested fluids.
Drills can be controlled for a prolonged time by dunking oysters in fresh water, or for a shorter period by dunking oysters in hot water. Alternatively, drills can be separated from oysters by drying the oysters out and placing them on 3cm mesh where the drills will fall through.