The Face of Boe is a being which appears to consist of just a gigantic, humanoid-looking head. Although he can only grunt vocally, he is able to telepathically communicate. (DW: New Earth)
The Face of Boe has the distinction of being one of of the oldest creatures in the known universe. This has caused him to be dubbed on some worlds as "the creature that God forgot". He was well known by the 51st Century, since Jack Harkness says that he once saw someone dressed up as the Face of Boe. (DW: The Stealers of Dreams) In 200,000, he was featured on BAD WOLFTV, where he was pregnant with six children (Boemina). (DW: The Long Game) In 200,100, he was the focus of a question on The Weakest Link, where he was described as the oldest living creature in the Isop galaxy. (DW: Bad Wolf)
In the year 5.5/Apple/26, the Face of Boe was the sponsor of an event to safely witness the destruction of the Earth by the expansion of the Sun. The event was sabotaged by Lady Cassandra, but the Face was among the survivors. (DW: The End of the World) By 5,000,000,023, the Face was hospitalised in Ward 26 of the hospital run by the Sisters of Plenitude on New Earth. Apparently dying of old age, the Face summoned the Doctor to him. When a novice told the Doctor the legend of the Face's last words, the Doctor realised that he fit the description of the "wandering traveller". The Face of Boe eventually recovered, saying that although he had grown tired of the universe, the Doctor had shown him a new way of looking at things. The Doctor asked about the message, but the Face told him that could wait for their third and final meeting, and teleported away. (DW: New Earth)