Dean Drobot/shutterstockLast year, 2015, was the year of the unicorn, a startup that raised so much venture investment, it was valued at $1 billion or more. But 2016 has become the year of the "unicorpse." Many unprofitable, once high-flying startups are having their come-to-Jesus moments: they may have problematic products, can't easily raise more VC money, no one wants to buy them, and no one is interested in their IPOs.