Lampent is a ghost-fire type Pokemon that debuted in the 5th Generation Pokemon Black & White games as the secondary evolutionary form of Litwick, and it is #608 in the Pokedex. It is shaped like an old-timey streetlamp with little arms, and it floats around without a pole.
Like its earlier counterpart Litwich, Lampent's light is fueled by the life energies and souls of those around it. Unlike Litwick, who slowly consumes whoever's nearby in small increments, Lampent actively goes out searching for dying humans so that it may harvest their souls once they die and use them for fuel. According to the pokedex entries, it likes to hang around hospitals specifically waiting for people to die. As if that wasn't enough, according to the Pokemon TV show, Lampent also occasionally partners up with Litwicks to lure humans to their deaths so that they can feed off them.
The Black, White, and B/W 2 entries, respectively:
"This ominous Pokémon is feared. Through cities it wanders, searching for the spirits of the fallen."
"It arrives near the moment of death and steals spirit from the body."
"The spirits it absorbs fuel its baleful fire. It hangs around hospitals waiting for people to pass on."
When Lampent is exposed to a special evolutionary stone called a Dusk Stone, it turns into Chandelure.