Daisenso

The Daisenso is Krieg's ultimate melee weapon, formed by locking his shoulder-plates against one another and activating internal devices that produce a shaft and a blade from between.

Abilities
In addition to its long reach, the spear's head explodes on impact with any solid surface, with heavier impacts produceing proportionally larger explosions; thus, even glancing hits or near-misses can wreak severe damage. To compensate for the blade's relative fragility, the explosive mechanism is stored primarily in the plates, allowing the spear to keep exploding even if the blade is completely destroyed.