Still more guns
Thresh's comments in BLACK
CalBear's comments in BLUE
The biggest toys
Thresh:
Dr. Mephisto's Warpo Ray
The Warpo Ray is the only weapon that comes with three firing modes. The first one is very similar to the sponge dart gun. It shoots piranhas at the enemy with a high rate of fire. Changing to shrink ray mode will eat up 10 ammo units but it's worth it. A good shot will shrink other players down to to a tiny size. The third and final mode also uses up 10 ammo, and will polymorph enemies into a harmless forest creature for a quick kill.
Cow Launcher
The Cow Launcher is sort of like the rocket launcher in South Park. Primary fire shoots one cow straight at an enemy, causing heavy damage, and unleashing a cloud of noxious yellow gas. The secondary method is probably the cheesiest way to get a kill. Keep the sights on an enemy for long enough and the launcher will lock on. Once that's done, right click and this will send the cow straight up in the air, and land on the target for an instant kill.
Alien Dancing Gizmo
Finally, there's the Alien Dancing Gizmo. It only appears in multiplayer though. The gizmo acts like a freeze ray in primary mode. Fire it at an enemy and the player will be paralyzed while dancing to a silly tune (though not the same tune that Cartman danced to in that one episode). While he's dancing you're free to drill him with other weapons. The secondary mode places the gizmo down as a mine. Anyone wandering near the device will be hit with the dancing ray, and will be paralyzed just as if they'd been shot with it.