The MPL is available in every Zombies map of Call of Duty: Black Ops. It is a sub-machine gun, and has a twenty-four round magazine. It is a somewhat effective weapon, but runs out of ammo very quickly. It is found in the second room on all five zombie maps in Black Ops, and can be bought for 1000 points.
When upgraded in the Pack-a-Punch, it becomes the "MPL-LF," obtaining a fourty round magazine and a red-dot site, with a random reticle.