Mew is normally described as a pink cat-like creature, though its morphology is actually more like a jerboa. Mew's hair is so fine and thin, it can only be seen under a microscope. It has a long, skinny tail. Mew has big hind legs, like a rabbit, and short arms with three-fingered paws. Mew has triangle-shaped ears and baby-blue eyes. Mew is said to have the DNA of every single Pokémon contained within its body. It also vaguely resembles an embryo or fetus, and is often depicted in a pink orb.
Mew's main abilities include turning invisible at will (similar to Rotom), creating force-fields of psychic energy and being able to transform into any one of the other 648 species of Pokémon. Mew is capable of wielding every type of attack possible. It also has the ability to float in mid-air, in much the same fashion as Celebi and Jirachi. It has been seen to be able to swim underwater as well.
Mew is a very curious and intelligent Pokémon that will only appear to someone with a pure heart. It loves playing around and swimming, and is known to act very childish at times, wanting everybody it trusts to play with it. It is attracted to lullabies and will try to stay as close to the music as possible. All in all, Mew is known as a happy, playful and optimistic species of Pokémon, unlike its clone, Mewtwo.
Reports found in the Burned Mansion found in Cinnabar Island in the Kanto region speak of expeditions of scientists, either independent or Team Rocket-funded which had sighted Mew in Guyana, South America, the place where its first sighting was reported. However, since Mew can either make itself invisible or transform itself into any other Pokémon, very few people have knowingly seen it, and it is called a mirage by most. Since many scientists believe that Mew is the ancestor of all Pokémon, and a number of extraterrestrial Pokémon have been discovered, it is possible that Mew could inhabit other areas of the universe, and whether it originates from Earth at all is debatable.
Considering Mew's unique lifestyle as a floating Psychic Pokémon, and that no terrestrial animal resembles it, there is no known diet for Mew. However, it can be found with the Lum Berry, which might offer a clue as to what it eats.
In the Super Smash Brothers anime, a Mew named Kris is a member of the Netfree Power Fighters. Little is revealed about her past, other than she had been friends with the other team members since childhood. The series does not detail how or when Kris became partially roboticized although an unused storyboard from the series indicates that such an origin was originally in the works. She has the ability to talk with telepathy.
Kris is seen only twice in her un-roboticized form during the TV series; in the episode "Super Conversion" a de-roboticizer is tested on her and is successful, although the effects are only temporary, and she returns to her previous state later in the same episode. The two-part episode "The Ultimate Blast" features Kris as a child, prior to her transformation. Mario time travels back in time, and rescues Kris from being turned into a robot earlier in history. Although his efforts ensure that the Power Fighters still exist in the present, Kris remains roboticized.
Kris's main asset was the tremendous strength afforded by her robotic limbs. Although her metal half works flawlessly for the most part, in the episode "Mario Passed Out", the telescoping ability of her legs (referred to as 'leg ladders' and 'ladder legs') cause her problems several times. In "Mario and Peach", her robotic arm malfunctions at one point; when Pikachu tries to help her up, he accidentally pulls her robotic arm off at the shoulder (this scene is edited out of the syndicated version of this episode, although it is included in the 2011 DVD release).
In this anime, another Mew named Kris has dreams of becoming a famous celebrity. In "Future Shock", Kris getting to go on stage is one of the main reasons Lime agrees to the idea of putting on a talent show at the Castelia Reversal. Kris's act consists of a cheerleader's cheer spelling out the name of the Castelia Reversal. Kris is also used as a back-up Skymobile for "real" Lugia Man and Ho-Oh Boy movie created by Jessie in "Lugia Man and Ho-Oh Boy: Movie Maker", much to her disappointment. She attends Castelia City High School. Her favorite band is an all-girls band called "Psyshockers" (a parody of Cascada, Nightcore and Kesha combined). At school, she is a member of the "Most Frequently Pictured in the Yearbook" commitee.
Kris has no interest in continuing the family restaurant business, largely due to her hatred of her friend and dreams of a more glamorous career. In "Go Kris!", Kris is brought in to help run the Castelia Reversal, and turns it into a girly teen cafe called "The Cuddly Mew", which, despite appearing to be very popular, fails to bring in profits, prompting Lime to tell Jessie to fire Kris, which she has difficulty to bring herself to doing. Kris reveals that she has been trying to be fired from the beginning, and that the business has been cutting into her "social life."