Face spider

Face spiders were a species of spiders with the the faces of babies. They were specially evolved to live at the back of wardrobes, though in the middle of the night they also lived in mattresses. The Eleventh Doctor checked for face spiders in Kazran Sardick's wardrobe when visiting him. However, it is possible that they were simply made up out of the Doctor's imagination, as it is a popular cliche to have monsters at the back of wardrobes; he may just have been trying to relate to or gain the trust of young Kazran. (DW: A Christmas Carol)