Harry's Species

An unnamed species of sapient humanoids. Only one individual has been encountered so far.

Resident Aliens (Comics)
This species are a grey skinned humanoid species. Their characteristics though include possessing pointed ears and eyes with dual pupils. Additionally they have a total of four digits on each of their hands. They have similar genders of male and female comparable to humans. Females are noted to sport long manes of hair while males have bald scalps though a few do short some facial hair. It is hinted that they can see into different spectrum of like such as infrared.

The species appears to have an innate ability to comprehend information at a fast pace, outstripping humans. They are able to have keen observant abilities, able to read human emotions better as they can detect micromovements of muscle and nerve changes that humans to them are transparent and able to see through lies. That added with the mental powers that the species possess they can create a psychic image of themselves to cast an illusion to appear human. Though the ability does have weaknesses as one in a million humans are immune to this. Their true forms can be perceived through other visual mediums such as videos and cameras though the species developed technology to disrupt and interfere with the former.

Resident Alien (TV Series)
These aliens are between 7-8 ft tall (~ 2.1 - 2.4 meters). They are also bipedal and extremely strong, able to throw an adult Human through a wall.

Their skin is blue/purple in coloration and has the ability to shape-shift into different forms.

Alcohol has the same effect on them as it has on Humans, hinting at a similar body chemistry.

Culture
In the comics the species are a peaceful spacefaring race. Due to their psychic nature, they seem to be comfortable in exchanging information via thoughts, even possessing couriers with the specific job to pass thought messages.