Anzor
From Tardis Wiki, the free Doctor Who reference
Anzor was a Time Lord.
Biography
Anzor was a bully of the Doctor at the Academy. Years later he encountered the Doctor's sixth incarnation, who was still traumatised by his experience with Anzor at the academy, and forced him into a locked orbit above the planet Magnus. However the Doctor betrayed his old classmate by causing Anzor's TARDIS to fly back to the big bang slowly, knowing his foe did not have the knowledge to reverse it.
Other information
His TARDIS was a type 60 and one form it took was an oak tree.