"Worms of the Earth" by Robert E. Howard

"Worms of the Earth" is a Bran Mak Morn short story by Robert E. Howard. As described by Weird Tales in its November 1932 edition: "A grim, shuddery tale of the days when Roman legions ruled in Britain—a powerful story of Bran Mak Morn, king of the Picts, and a gruesome horror from the bowels of the earth."