In the 1966 TV series, the Klingons
looked like they had bad tans, and no
calloused-ridges on their heads.

A few decades later, we got Star Trek
the Next Generation with Klingons [black, brown and white]
with those calloused-ridges on their heads.

Maybe they all became "headbangers"? ;-)

I'm stuck on Klingons and Klingons stuck on me. Get it????

But seriously: The original and later ST series did
present aliens that were sublime [transforming like butterflies],
aliens that were silicon-based, not carbon.
And even aliens that HAD NO BODIES.

Some of you refuse to accept the idea/theory that some or many hypothetical
aliens may have NO physical bodies at all...I assume your disbelief
of that hypothesis stems from your view that it smacks of
mysticism or spiritualism....
Well?... Reality, whatever and wherever it is, hitherto unverified or not, is still reality; whether we perceive it now or NOT...verification will
eventually come sooner or later.