Hammerspace Knife

''As far as knives went, they were massive things, easily a foot long and two inches wide, while the actual design of the blade and handle strongly resembled a Bowie knife. The blades were polished to a fine sheen, looking incredibly sharp, while in the handle he found a small hammerspace generator, explaining how the Sue was able to summon them and make them disappear with barely a thought...'' -- "In which M*A*S*H is defiled by a Sue, Radar is shipped, and Marcus enacts vengeance.", Marcus' examination of the hammerspace knives.

Hammerspace knives, named for the generator built into the handle which allows the wielder to bring them into and out of [Hammerspace] at will