Let us look at a situation. Your parents have told you to go down stairs to get some sort of canned food item. You go down but half way down the stairs you forget why you went. So instead of going to the food storage you go to your room and start reading or doing homework. Later your parents ask you why you forgot and all you can say is "I don't know".
There is an explanation...The Silence.
This is a alien race that hasn't invaded the planet, they have lived here for as long as we have and even longer (why it took The Doctor so long to finally fight them we may never know). They have the ability to erase themselves from your memory. The only time you are aware of their presence is when you are looking right at them. But as soon as you turn away, you forget about them.
They can however implant ideas into your mind. Any time you have ever had a random idea, or a sudden flash of inspiration, that could have been one of the silence telling you to do something. But since their ability makes us forget about them, we think that the idea was ours (our you are genuinely a genius...highly unlikely...not that I don't have faith in your mind power....it's just more likely that it was The Silence)
The eveidence of these creatures are everywhere. The unexplained creek in your house. The random door closing, the breathing under your bed and the voices in the wall. Have you ever turned your head and you thought you saw someone but when you look back there's no one there? And then a couple seconds later you forget you even did that untill it happens again or someone brings it up. They are the explination for why you suddenly get scared of being alone even though you were perfectly fine. The reason you think someone is watching you.
The creator of the creations said that these creatures where to be the scariest monster yet. As it has been said, the Weeping Angels are commenly considered the scariest. Here is the question: Which is scarier? The Weeping Angels or The Silence?
Personally I think the Weeping Angles are scarier for these three reasons.
1)You cannot kill them. Silence can be killed by a gun or well placed kick.
2)They are so fast they can kill you in the blink of an eye. Silence are dressed in dress clothes and everyone knows that it is impossible to be fast in a suit.
3)You can see and remember a weeping angel.
Here, however, are three things that I like about The Silence
1) They look cool in their little suits
2)The thought that they are eveywhere and we don't know it is pretty cool. There is nothing scarier than something you can't see.
3)The idea of post hypnotic suggestion explains a lot.
Feel free to say which monster is scarier and some reasons why. They don't have to be long like mine...I just like to hear myself talk...or...read myself type...read what I typ.......Just comment...