Street urchin (Attack of the Graske)

From Tardis Wiki, the free Doctor Who reference

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 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)