Self Destruct is an extra in Lego Star Wars: The Complete Saga, and Lego Star Wars II: The Original Trilogy. When turned on, if you are any droid in the game and press Z, or Y, you will blow up. It is useful for taking out large masses of enemies and can blow up shiny objects that usually need a thermal detonator to blow up. In Lego Star Wars II, it is unlocked after doing the level Hoth Battle, and can be purchased in the Cantina for 20,000 studs.