Litwick seems to be based upon a lit candle. It is white and cylindrical in shape with small yellow eyes, one of which is hidden by what appears to be a flap of melted wax; the drooping wax covers and encircles the top of Litwick's head. It has small stubby hands and a small grinning mouth that appear to be drips of wax. Due to its Ghost typing, Litwick's ethereal body is incapable of melting. The flame on its head is of purple color and has supernatural qualities.
As a Ghost type Pokémon, Litwick tend to be mischievous and cruel. It tends to live in old mansions and dilapidated places. It lures people and Pokémon with its mysterious purple flame, only to later trick and frighten them and absorb their life energy.
In BW029 A group of Litwick appeared where they, along with a Lampent tried to attack Ash and friends, Jessie, James and Meowth. When Team Rocket sought to make the abandoned mansion the Litwck inhabited into their Unova headquarters, the Litwick decided to play them for the fools they are and suck out their life force to keep their candles burning. However, they were stopped.
Litwick's cry starts off high pitched but echoes near the end almost sounding like its in a cave.
Litwick's "hairstyle" appears to be based off the wax that drips off a candle while burning.
Despite being known to leech life energy, it can not learn any draining moves.
In Pokémon-Amie, one can pet a Litwick's flame and not be burned by it, instead, it will cause the "Transparent Hand" affect which is common from petting Ghost Types in Pokémon-Amie, it shares this trait with its evolutionary family.
Litwick is based on a haunted candle. The purple flames of this Pokémon's line are a play on the depiction of ghosts/spirits appearing as ghostly flames/lights in Japanese culture, or the legend of the will-o'-the-wisp.
Litwick's name is derived from the words "lit", "little", and "wick" or possibly "wicked" (on account of its highly mischievous ways of tricking people and Pokémon).