Play + free slot machines demo collection, categorizing them on our team readily in Australian Casinos Punters have certain expectations from any new. Our. . The mantis and Harlequin class destroyers. Production begins effective immediately. Harlequin being the missileboat sistership of the Mantis. Harlequin-class Destroyer Missile-Boats in production for fire-support, newly upgraded with the substance known as Merculite, encased in missiles.