What do aliens look like?

[Scarim Coral]

I would imgine the alien to look nothing like human at all (not humanoid).
As for favourite alien I guess it would be him-

Spoiler: Jonn Jonzz AKA Martian Manhunter

 

[Hazy992]

There's no way of knowing and speculation is pointless. Just look at how varied life is on earth;

Spoiler: Jellyfish

Spoiler: Lion

Spoiler: Scorpion

It's almost hard to believe that these all come from the same planet. Imagine what life on another planet could look like?

 

[Hazy992]

like this of course

Spoiler: Image

Oh dear God no! CANNOT UNSEE!!!!

 

[Mr.Mattress]

They'll look like Alf.

And they will be just as annoying. Quickly, Hide your cats!

 

[Rowan93]

On another planet, they may have equivalents to Tyrannosaurus, and those may not have been wiped out by a meteor strike sometime in the distant past. If so, there's no reason why intelligent life couldn't have evolved from large, ferocious land-based predators, as opposed to small primates as here on Earth.

Actually, there's definitely a reason there - great big land-based predators tend to evolve into predators that are better at predatoring. Sure, it wouldn't have to evolve from primates, but it'd have to evolve from something in the same kind of niche as primates like Australopithecus occupied on earth, because otherwise it wouldn't have the right set of selection factors to end up with enough intelligence to invent tools and become rulers of the planet.

It all depends though. A great big land based predator won't have much need for tools, but successive generations of predators that are smaller and weaker will perhaps necessitate a need for the evolution of tools and higher intelligence, lest they be killed off or die of hunger.

I didn't mean to get hung up on a particular example. To assume that other planets even have large land-based life-forms in any way comparable to T-rexes or the like is an act of great optimism and naivete. The point is that we cannot use Earth as any kind of basis for what to expect to find on other planets. Intelligent life may evolve, for instance, on a gaseous planet with less than a tenth of the gravity of Earth. Life there would have no need for a humanoid form replete with arms, legs and thumbs when a gaseous, balloon-like shape would better suit the environment. Over the course of billions of years (remember, the Universe has had the potential to host life for 15 billion years), this hypothetical planet may have evolved super intelligent beings that look more like Zeppelins than anything else.

Humans evolved from animals that lived in trees. That's why we have opposable thumbs and fingers, limbs that can rotate freely, and why our cousins the monkeys have long, prehensile tails. If life evolves on a planet completely devoid of any form of tree-like life, why would the primate template be necessary? A planet covered by the equivalent of grasslands and plains would have no need for humanoids or primates with grasping limbs and tails, when herding life-forms equivalent to buffalo and antelopes would be far better suited.

But how would successive generations become smaller and weaker? That's the exact opposite direction to where evolution is pushing them, big predators tend to get faster, stronger, and grow bigger teeth. Something has to be on the fringes in order to have to start innovating.

Oh, no, I'm sure there are lots and lots of planets without large land-based lifeforms. But that's necessary in order to end up with any kind of computing thing being needed, so finding those planetary ecosystems will just be several oceans' worth of slimy bluegreen disappointment.
Oh, wait, you meant gas planets? Well, that's at least a possibility, just as long as you're not talking about that environment's apex predator being where the intelligence comes from.

I didn't say anything about trees, I said the same kind of niche. Australopithecus walked upright because it didn't live in the trees any more, but it didn't have any kind of human-like civilization - whatever niche it fitted into as an animal, you need to start with a similar niche to get sapient alien life. It only has to be similar in terms of the selection factors, which makes it a pretty broad category, but it definitely has to be in there.