You've heard the overused neologism unicorn, which describes a startup with a valuation above $1 billion. The idea was that such highly valued startups were so rare that seeing one was as rare as a unicorn sighting. Now there are herds of unicorns roaming Silicon Valley. At last count, there were 131 in the tech industry. In fact, startups have become so valuable that there are now some that are worth more than $10 billion. These are called "decicorns."