Aliens have been documented in hundreds of types and sizes, from 3 inches up to 15 feet tall. Some walk on two legs and others are shaped like balls of light as small as a golf ball or as large as a house. Some aliens look like robots, metal objects, or animals. Other aliens look like giant insects or praying mantises. Some wear clothes or uniforms, and some do not.
Some aliens float through walls and others walk in through open doors.
Their skin can be warm or cold, wet or dry. Skin colors are gray, white, tan, brown, gold, yellow, green, blue, pink, orange, red or black, along with other shades in between. Their eyes can look like a human, cat, lizard, insect, alien, etc. Some have fingernails and some don't. Some have webbed fingers and others have suction cups for fingertips or claws or pincers.