Kozmik,
When I saw the mantis type fellows I was on a large ship filled with different species including this one.
I am not happy with how thin the rear legs are in this picture also the neck should be thicker and a bit shorter, but these beings were semi
quadruped.
Sorry Mr Andy.
I do agree that the reason most E.Ts are bipedal is because this shape makes a lot of sense. I think that evolutionary convergence at work, a huge
number of sea creatures are fish shaped, but there are exceptions to that rule, with more exotic shapes that do the same job.
The bipedal symmetrical four limb shape is well suited for intelligence, but I think that there are other more exotic shapes out there as well.
Kozmik, the Mantis folks didn't seem particularly evil, just really, really weird looking.