There is a new wave of fear of strong AI, based on writings by Nick Bostrom, especially his book 'Superintelligence'. Elon Musk has helped to spread the word.
Unicorns are much the same. From the look of them, you'd imagine they must have gored at least a few people, but then you remember they don't exist. If we feel compelled to fear something, we can probably find more immediate dangers.