What do you think an extraterrestrial would look like if you saw one?

well depending on how evolved they are, they would probably look somthing like the other creatures on their planet for example, if most things there has eight limbs, they probably would too so in my opinion, i would have to imagine an entirely new ecosystem to think about what an extraterrestrial might look like.

It's almost impossible to predict. Really you need to start with the nature of the planet they come from.

Planets with light gravity would produce tall and gracile creatures with the need for high sensitivity of smell and sound in order to function in a thin atmosphere.

Planets with Heavy gravity would produce short squat powerful creatures with large eyes and tough skin to protect in a thick atmosphere and crushing pressures.

There's certain prerequisites for an intelligent species which will posess the necessary technology to talk to us. They must have a highly rational understanding in order to utilise advanced mathematics - which will be the universal language if we ever contact anyone out there. They must also have the manual dexterity in their limbs to work metal to a high degree of precision or they could never be effective electronic tool manufacturers.

If they're fish for instance, they could never work metal so even if they were cleverer than us, they would never have entered a bronze age so would remain a technologically primitive species.

They must have highly developed nervous systems but not necessarily huge brains. We don't know how an alien physiognomy could retain information. The phyla we're used to here could mean little out there in the cosmos (such as the 2 arms 2 legs pattern), but it's logical to assume certain aspects of evolution would run on parallel lines if the planetary environment is similar to earth's. Insects will be abundant, reptile and mammal like creatures would be dominant.

For personal reasons I believe the real aliens or at least the ones I may be aware of are aquatic. It sounds silly I know but I think they look kind of like jelly fish of sorts.