The idea of ‘killing the Buddha’ comes from a famous Zen line, the context of which is easy to imagine: After years on his cushion, a monk has what he believes is a breakthrough: an experience of nirvana, the Buddhamind, the big pay-off. Reporting the experience to his master, however, he is informed that what he has experienced is par for the course, nothing special, maybe even damaging to his pursuit. And then he is given dismaying advice: If you meet the Buddha, he is told, kill him.

Why kill the Buddha? Because the Buddha you meet is not the true Buddha, but an expression of your longing. If this Buddha is not killed he will only stand in your way.

From the Manifesto of http://www.killingthebuddha.com/ better known as the radical (in just about every sense) theological e-zine 'killing the buddha.'