Cybermen

The story you remember is probably...

Earthshock (1982).

A Cyber Army hid themselves away in cylinders on a cargo cruiser bound for Earth.

Once revived, they wrest control of the ship away from Captain Beryl Reid, and send it hurtling back 65 million years in time.

When the ship hits the Earth, it not only destroys the dinosaurs, but also the Doctor's companion, Adric. Tragic.

Find out more in the Earthshock episode guide.