Gengar (ゲンガー Gangar)

-Name Meaning- Gengar's name is probably a shortening of doppelgänger - a ghostly double of a person. This is a fitting name for a Pokémon with a habit of pretending to be a person's shadow.
-Evolutionary Line-
Gastly (25),

Haunter (Trade),

Gengar
-Pokedex Entry-It hides in shadows. It is said that if GENGAR is hiding, it cools the area by nearly 10 degrees F.

Type: Ghost/Poison
Species: Shadow pokemon
Ability: Levitate
Height 4′11″ (1.5m)
Weight 89.3 lbs. (40.5kg)
Egg Group: Indeterminate
National Dex: #094
Johto Dex: #060
Hoenn Dex: #264
Fiore Browser: R-096
Sinnoh Dex: #071

-Weak Against-Ghost, Dark, and Psychic
-Strong Against-Normal, Fighting, Poison, Ground, Bug, and Grass
-Biological Characteristics-Gengar often has a rather sinister personality, especially when in the wild. It inhabits remote mountainous locations and urban environments alike, being a dangerous Pokémon to encounter in either case. Fortunately, Gengar is a nocturnal Pokémon, so its attacks are limited to the hours of darkness.
Gengar tends to stalking its prospective prey, which includes human beings, and hide in their shadow. It is said that in this way, it has the opportunity to absorb the "vital force"/life of its victims. Gengar acts like a heat sink while doing this, so that its malevolent presence can be given away by a feeling of cold and a shivering sensation.
Another favorite pastime of Gengar is to mimic the shadows of people. A common prank is to take the shape of one's shadow and run past him, giving him the impression that his shadow has come alive and overtaken him. Gengar especially loves to frighten people that way during the nights of a full moon. Gengar's eyes can glow in the dark.
-Special Abilities-The ability Levitate allows Gengar to hover slightly above the ground. This means ground type moves have no effect on them! (I say this is a good thing because Ghost/Poison vs Ground? Ouch.)
-Diet-
-Other-
All info from Bulbapedia!