If you play the English Opening and like to use the Four Knights system, you should be prepared to face the Bellon gambit. While speculative in nature, the gambit poses White problems that an unprepared player probably couldn't solve over the board. The idea is inspired by the sometimes trendy Wing Gambit in the Sicilian.
In this game, Wolfgang Uhlmann defeated Juan Bellon, the Spanish GM and chief exponent of this line in the English.
This game occurred in Bucharest, 1978. If you study this game and the annotations, you will be better prepared to face this arcane postscript in the English.