Cave creature
From Tardis Wiki, the free Doctor Who reference
The cave creature was a being on Setarus in the Divergent Universe. It was psychic and captured Major Koth and examined him. It could tell that the Eighth Doctor didn't come from it's world. It could bind with people and feed off their emotion. When Byzar Janto bonded with it, it died from heart break. It stole the Doctor's TARDIS. The Divergence placed it in contact with Koth. (AUDIO: The Twilight Kingdom)