In Starcraft 2: Wings of Liberty for the PC, there is a cheat increase your damage output, and it also has an added bonus of making you invincible. During the game hit the Enter key to bring up the message prompt and type in terribleterribledamage to enable the cheat.
Note that once cheats are turned on, you will not get achievements for that game.
Check out my other article for more Starcraft 2: Wings of Liberty Cheats.