Call of Duty: Black Ops Easter Egg - Secret Weapon Easter Egg: Thundergun

1.) Load up the Black Ops campaign mission "Numbers" on any difficulty.

2.) After the gas is released in the first room, turn around and go behind the desk. You'll see a black cassette inside of a player. Activate the cassette, which in turn makes it disappear.

3.) Proceed to Clarke's armory.

4.) Once inside the armory, go to the left and activate the player on the table, making sure to hold down the activate button.

5.) Take the Thundergun and enjoy!

Notes:

In the Nazi Zombies mode, there's a chance you'll be awarded the Thundergun from the random weapon chest. Upgrade this weapon to receive the Zeus Cannon. Whoo!