Perhaps the most surprising announcement at Bethesda’s first E3 press conference earlier this week was a Fallout-themed mobile app known as Fallout Shelter. The app, which launched on iOS shortly after the announcement and is expected to hit Android soon, looked like a fun way to distract yourself while waiting for Fallout 4. However, it appears as though the game could be a potential cash cow for Bethesda, as just three days after its release, the app has surpassed Candy Crush Saga in popularity.