The Teller was a large humanoid telepathic creature with an eye stalk on either side of its head. It was able to sense guilt in others by scanning their thoughts. It was also capable of emitting a form of energy that could liquefy the brain, causing the crown of the head to "cave in". he was only ever seen in The Time Heist opposite the Twelfth Doctor and was superbly played by Ross Mulan.  Ross was the first actor ever to get two figures made by us of himself. I am very happy to say this lovely man was really pleased with both of them.