From Bloomberg Nov 4, 2011:

Warren Buffett’s Berkshire Hathaway Inc. (BRK/A) said third-quarter profit fell 24 percent as derivative bets declined in value.

From BBC March 4, 2003:

Mr. Buffett argues that such highly complex financial instruments [derivatives] are time bombs and “financial weapons of mass destruction” that could harm not only their buyers and sellers, but the whole economic system. Some derivatives contracts, Mr. Buffett says, appear to have been devised by “madmen”. In his letter Mr. Buffett compares the derivatives business to “hell…easy to enter and almost impossible to exit”…

He might be rich, but let’s face it: he is one manipulative character.