1. e4 2. Ke2!!!!!

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SuddenLunch00

The bongcloud is the best opening. After white plays 1. e4, he plays 2.Ke2!!! and suddenly, black has no choice to resign. If Black goes on, he will lose because White's king is more developed for the endgame. 

Look at this game:

If the PGN doesn't work...
1. e4 e5 2. Ke2!! {Black is gone! He can't do anything but resign. But if he continues...} 2...f6 {Forced.} 3. Ke3!! {And white has a decisive advantage with his better king} 3... g5 {Forced. Otherwise, Black will die immediately on the spot} 4. Qh5+ Ke7 {Black tries to develop his king, but it's too late. From here, white has a forced win} 5. Bc4 a6 {Forced, once again} 6. Qf7 Kd6 7. h4! {Undermining g5, an important defensive pawn on the kingside that won't let the king develop.} 7... Kc5 {Black continues developing, but its too late} 8. hxg5 Kb4 9. c3+ Ka4 10. Qd5 11. h6 b3# 1-0 {Black was too late to stop white's rampaging king}