https://www.runjeetsingh.com/inventory/209/scissor_katar

Katars are already interesting weapons but some, like this scissor (or kenchi) katar, hold a surprise: squeezing the bars that form the grip causes the single blade to instantly split into two and reveal a centrally placed third. Such a mechanism suggests that this katar was an expensive and high status product, not just for the owner but also for the weaponsmith that made it.