The primary COG weapon, the Lancer. This is the workhorse of the COG army. It is intended for mid-range combat, but features a chainsaw bayonet for when you feel like getting up close and personal. Press and hold the melee(B) button to activate. If you take damage while using the chainsaw, it will stop running and you will need to press B again to start it.
When attempting to use the chainsaw bayonet, it's best to rev it and then run into the enemy. While the chainsaw is revved, the controls change to make it easier to look around while still holding B. You use the left stick to move forward and backward as normal, but you also look left and right using the left stick. This is quite useful for when your enemy moves to the side while you're trying to chainsaw them.