Replying to the OP if the aliens could look like us....
The ones captured in in Roswell in 1947, called greys did not look like humans, they had a humanoid type body however.
May be aliens from other galaxies look more like us.... who knows.
from Wikipedia:
Appearance
Greys are typically depicted as dark grey-skinned diminutive
humanoid beings that possess reduced forms of, or completely lack, external human
organs such as noses, ears or
sex organs.
[2] Their bodies are usually depicted as being elongated, having a small chest, and lacking in muscular definition and visible
skeletal structure. Their legs are shorter and jointed differently from what one would expect in a human. Their limbs are often depicted as proportionally different from a human's; their
humerus and thighs are the same lengths as their
forearms and
shins, respectively.
[2]
Greys are depicted as having unusually large heads in proportion to their bodies. They are depicted as having no hair anywhere on the body, including the face, and no noticeable
outer ears or noses, but only small openings or orifices for ears and nostrils. They are depicted as having very small mouths, and very large opaque black eyes with no discernible
iris or pupil. Reports of alleged encounters state their height to be 2–4 ft tall, but may be human size or taller as other varieties of greys have been described in various claims.