The Plasma Pistol returns from Halo: Combat Evolved. It is an energy weapon that cannot be reloaded by the Master Chief and as a result, must be discarded after use. The weapon can also be dual-wielded for maximum effectiveness.
Plasma Pistols have two firing modes: a manual rapid-shot that can slow down and stun opponents (much like the Plasma Rifle), or a powerful overcharged bolt of plasma that is able to deplete an enemy's shields. However, after overcharging the weapon, or shooting manually in rapid succession, the weapon must cool down before it can be used again.