For most people, a unicorn is a mythical horse with a pointed horn in a flutter of fairy dust, but in Silicon Valley, it's a pre-IPO start-up valued at $1 billion or more. If a collection of these beasts of the fairy dust variety is called a blessing, the proliferation of Silicon Valley unicorns is anything but, as more and more of then become "unicorpses."

A "unicorpse" is venture capital parlance for an overvalued start-up, galloping into oblivion.