These were the robots which were forgotten about by the human race.
The Mechanoids were built of Earth and were sent to the planet Mechanus to see if human colonists can live there. Unfortuantly the Mechanoids were forgotten about and left in their huge city which was above the ground of the forest. When the Doctor, Barbera, Ian and Vicki were trapped by the Daleks a Mechanoid saved them and took them up a lift to the city.
Once they got there the Mechanoid locked them up as prisoners forever. The Mechanoid would study them as they looked through the windows like the Doctor and his friends were zoo animals. Another human was with them, Steven who built a huge wooden ladder leading to the roof. The Doctor and his friends were going to escape from the roof.
Meanwhile the Daleks invaded the Mechanoids city and a war began with the Daleks facing the Mechanoids. A few Daleks were killed and a few Mechanoids were blown up. The city then caught on fire and the Doctor and his friends quickly escaped from the roof. The city fell down and was destroyed killing all of the Mechanoids and the Daleks who had chased the Doctor and his friends throughout time and space.
The Mechanoids appeared in:
Season 2: The Chase