Rotom (Japanese: ロトム Rotom) is a [ genderless ] dual-type Electric/Ghost Pokémon.

While it is not known to evolve into or from any other Pokémon, it has the ability to possess the motors of certain appliances and change forms.

When it does not possess an appliance, it is Normal Rotom, and is Electric/Ghost.
When it possesses a microwave_oven it becomes Heat Rotom, and is Electric/Fire.
When it possesses a washing_machine it becomes Wash Rotom, and is Electric/Water.
When it possesses a refrigerator it becomes Frost Rotom, and is Electric/Ice.
When it possesses an electric_fan it becomes Fan Rotom, and is Electric/Flying.
When it possesses a lawnmower it becomes Mow Rotom, and is Electric/Grass.

Depending on the game, its form can be changed at will in Rotom's Room in the Team Galactic Eterna Building, Rotom's Room in Silph Co., the store room in Shopping Mall Nine, on the second floor of Professor Sycamore's Lab in Lumiose City, or in Professor Birch's Lab in Littleroot Town.

In Generation IV, it was Electric/Ghost regardless of its form.