M363 sticky detonator

This unidentified UNSC weapon appears in the Halo 4 announcement trailer. In the trailer, John-117 grabs one such weapon floating in zero gravity and uses it to blow a piece of debris out of his way whilst escaping the exploding wreckage of the.

Sized like an ordinary sidearm, the weapon appears to fire explosive munitions attached to the muzzle, reminiscent of rifle grenades. There is a pair of rails below the barrel, possibly for securing the grenade in place. The weapon's reloading mechanism resembles a breech-loading system; the weapon's upper half flips open and a new cartridge is inserted before closing the covering. Whether the weapon has other firing modes is unknown.