Street urchin (Attack of the Graske)

An urchin boy begged for money on Christmas Day, 1869, after the orphanage he lived in burned down. An alien Graske stole him and replaced him with a Changeling. The Tenth Doctor, with help from the Viewer, destroyed the Changeling and brought the urchin back, with no memory of the previous events. (DW: Attack of the Graske)