This is based on a game between Simagin and Polugaevsky in 1961.  The previous move by black was not made in the actual game (Nc4), for reasons that will become apparent pretty soon.  To a moderately skillful player it would appear forking the white Queen and Bishop with Nc4 is a good idea, quite wrong.

 

The move made in the actual game by black instead of Nc4 was f6 (certainly the lesser evil!).

Nice puzzle got it in 30 seconds thanks 4 sharing.

wow ery nice:)