The Mantis Shrimp is a beautiful animal, but care should be taken when adding one to your aquarium. There are two hunting categories of Mantis Shrimps: the "spearers" and the "smashers". The "spearers" use their spear-like claw to silently stab soft tissued prey. The "smashers" use their forceful, club-like claw to hit, crack open or pulverize harder bodied prey.
Dr. Roy Caldwell provides More Information About Mantis Shrimps.