I believe the Martians have been used in more science fiction novels than any other imaginary species. When we eventually find them I expect they will turn out to be the most peaceful race in the universe and will be quite shocked to find out how often they have been used to destroy the Earth purely to assist in making a good story.
In my novel they are the hidden controllers of the staff of the Weber Institute. I did this because I enjoyed the irony of one group who think they are superior to everyone imposing their will upon the world but are actually unaware they are being controlled themselves. Happens to me all the time. Their main use however was to help me try and portray what it is like being in a four-dimension space-time.
I wanted to make the Martians completely different to us, and I mean different. In my novels they are fairy like in appearance and are able to live and see in a four dimensional world. Which means they have to exist in five dimensions (see my section on Understanding Time). In this 4D world of theirs they do not see us as we see ourselves. They actually see a little of our past and a little of our future in our shape. To understand this, you have to imaging taking a short movie of yourself. It is a special movie where instead of each frame joined side by side they are stacked on top of each other. After a while you will have a pile of frames a few inches thick. Now if you then cut out your shape where it appears in the stack and lift it out that will give an idea of what we look like to them. Except of course as we move through time this extended shape will be continually changing.
Because they can see a little into the future I decided to make things a little more complicated. At each point in time I postulated that there were a number of futures available which we poor 3D creatures cannot see but they can. The Martian are not able to change these futures but they are able to slide from one to another as only a 4D or 5D creature can. The hero and heroine have this ability as well but they don’t know why nor do they seem to have any control over it.
Because of this ability the Martians have no concept of what we are really like. However, they have a rudimentary form of telepathy which they can use as an anaesthetic to slow down 3D creatures so they can see them more clearly but it also allows us to see something of their world. I think fairies have the same ability as well. This is why they prefer to visit us at night when we are normally fairly immobile or asleep.
So what do they look like?
Here is a description of a Martian from my short story Time Fracture where one materialises in the Time Travellers home.
“The creature was ghostly white, only about three feet tall and very thin and floating above the ground. It was disconcertingly familiar like a character from Lewis Carroll. The head was like that of a cat but its ears were more like a rabbit’s. Its eyes were wide set and bulged and blinked like a frog’s and protruding from its shoulders were two small wings which seemed to shimmer iridescently as though they were not part of its body.”