Re: Aliens: everything you know is... well, "wrong" doesn't even begin to cover it.
When designing 'realistic' aliens, I follow the "octopus" rule of thumb. - since every macroscopic part of an octopus evolved apart from us (our common ancestor would be a worm), that if an alien is as different to us as an octopus AND if it is a different to an octopus as we are, then I have made my alien sufficiently alien