Speculating about what aliens look like has kept children, film producers and scientists amused for decades. If they exist, will extra terrestrials turn out to look similar to us, or might they take a form beyond our wildest imaginings? The answer to this question really depends on how we think evolution works at the deepest level.
Hollywood has given us its fair share of humanoid aliens over the years. Initially this was through necessity, as special effects required someone to clamber into a rubber suit.