Harry Trant was a space traveller.
Biography
Harry was travelling in his spaceship when was swallowed by a living planet. After escaping the planets mouth, Harry spent around a week on the planet's bare surface. It was on the planet's surface where he met the Doctor, whose craft had also been swallowed by the planet. Together Harry and the Doctor managed to make their way into the planet's stomach, where the Doctor used his TARDIS to escape the planet. The Doctor then took Harry back to his home planet in the TARDIS. (TVA: The Hungry Planet)