Simply calling it "Pacoo" might be a misnomer, but titles like "Mister" and "Missus" aren't allowed.
Talk about it here.
Mr. and Mrs. Pacoo were two avian humanoids who were guests on Platform One to watch the Sun burn the Earth in the year 5,000,000,000. They had almost identical appearances. The two survived the near destruction of Platform One, but mourned the loss of others like the Moxx of Balhoon. (DW: The End of the World)
The Pacoos, along with the other survivors of Platform One, were later kidnapped by the Elth of Balhoon, who believed that they hadn't tried to help the Moxx of Balhoon and had abandoned him to die. They were rescued by the Tenth Doctor, and not only forgave the Elth for kidnapping them, they offered to help him. (DWBIT: Reunion of Fear)