Terries and Fermies

The Terries and the Fermies are two kinds of creatures who live underground. They first appear in "Land Beneath the Ground!" by Carl Barks.

They tell each other apart by the ties they wear on ribbons around their necks — the Terries wear bow ties and the Fermies wear four-in-hand knots. They locomote by folding their head and arms into their body so they become a perfect sphere and then they roll from place to place like a bowling ball. They are colored various bright colors. They have periodic contests on an irregular basis to see who can cause the biggest earthquakes. Terries cause earthquakes by rolling in massive groups of thousands against the giant pillars that support the land on the surface of the earth. Fermies cause earthquakes by gathering together in massive numbers and lifting up pieces of the Earth's crust. Whichever group causes the biggest earthquake wins the contest and gets the prize, a piece of Ancient Greek pottery that fell down a crevice in Ancient Roman times (later replaced by Scrooge McDuck's hat at the end of the story).