The Wronsdehj had six ears and two mouths: an upper mouth and a lower mouth. According to the Fourth Doctor, when their home world was destroyed, they made a habit of conquering a planet, using its inhabitants as slaves, then a few months later destroyed the planet, moving on to the next one.
They conquered parts of Europe in the 22nd century and enslaved the citizens. Rabbi Gnom Burstein and the Doctor freed the Golem of Prague from the Altneuschul. The golem, with some help from K9, defeated the Wronsdehj, causing them to flee the Earth. (PROSE: Life from Lifelessness)