Good question. The Economist compared the EU to a triceratops, a big, extinct, dinosaur, generally believed to be a plant eater along the lines of the dinosaurian rhinoceros. Only with more horns up front. Then they went on to call for conversion of the triceratops into a gryf.
So what's a gryf? Tarzan, on one of his adventures into darkest unexplored Africa, encountered them, and they looked like triceratops (Tarzan even recognize them as such in the book) but they were ferocious man eaters instead of herbivores. I happened to have read that very Tarzan book as a child. My summer camp library had a copy. The book (Tarzan the Terrible) was published back in the 1920's and I never saw it for sale anywhere. It's like really out of print.
Anyhow, an Economist writer read the long out of print Tarzan book, and thought the Edgar Rice Burroughs fictional monster would make a good simile or metaphor in 2017. Groovy.