The Silents

'The Silents', aka Mini Slendies, were servants of the Demon of the Abyss who controlled humankind from the shadows and apparently had done so for centuries. They have the ability to edit themselves out of the memories of individuals if they are not being observed, so if you see one and look away, you forget you ever saw him. After a millenia of servitude to the Demon, the Silents rebelled against her/it after getting their shiny bald asses walloped by the Doctor, and they later defected to the Pantheon of Dischord.

They also have the ability to blast people with lightning, and they open their mouths when doing so, oddly. They seem to kill random people for no reason, usually if they're going to the toilet (odd). They also have it in for the Doctor because he almost annihilated their entire species by broadcasting an image of them on national television, making everyone remember them and causing a psuedo-genocide as the human race brutally massacred the suprised Silents, then forgot they had ever done so.

The Silents themselves aren't very Silent at all, they make a horrible rasping sound if someone is close to them. They also have the ability to control people by telling them to do something when they are looking at them, and then when they look away they will do it, not realising that someone told them to. This is known as a post-hypnotic suggestion, and it is what the Silents use to control humans.

After the massacre that nearly destroyed their species, they fled Earth in a Human-made rocket (since Silents themselves have no technology of their own, thus they are failures) but they were soon marooned in deep space. Woe to any space traveller who finds the derelict craft...