Spekra

Spekra was a planet inhabited by a Near-human race ruled by Gritog, and by dinosaur-like creatures similar in appearance to the Apatosaurus. When a spaceship from Earth entered Spekran space, Gritog had his fighters force the vessel to land and imprisoned its crew, believing them to be spies. Shortly afterwards, the First Doctor, John and Gillian arrived on the planet in the TARDIS. After discovering the prisoners, the Doctor used an ultrasonic flute-like instrument to summon two of the creatures to break down the prison walls and take the prisoners back to their spacecraft. Afterwards, they returned to the TARDIS and departed Spekra. (TVC: Prisoners of Gritog)