Ferran is the companion of the Professor, a time lord in the form of an earth pony. He is a changeling, who was revealed to have escaped his hive. Little else is known about him, or what happened.
Such information is unknown, even by The Professor.
He looks like a normal changeling, exempting his mane, tail, and his carapace. His mane and tail are some sort of a lime, or a shade of green being more blue than green, and the color of his carapace is light shade of green.