It seems that unicorns do exist and they have been around for a while.
A Unicorn is a start-up company valued at over $1 billion, and private investors have put $362 billion over 5 years. Thus pumping up the paper value of unicorns, the largest being Uber, Airbnb, Pinterest and Dropbox.
There is concern that this rate of investment has created a risk-bubble for these unicorns. As over 100 tech companies passed into the unicorn range the fear of a bubble has risen.
I am sure it will be a bumpy ride for all of us as any and all markets shifts lately seem to impact the whole economy.