Rotom has a body of plasma and is shaped like a lightning rod. There is a whitish blue aura of electricity around it that forms lightning bolt-shaped appendages. It has teeth, and its unique, blue eyes have a dividing line across them. As seen in the anime, Rotom will often pull pranks on unsuspecting people. Also seen in the anime, Rotom has the ability to time travel.
Rotom and the appliances
Rotom has the ability to enter and control appliances. Starting in Platinum, it also has five extra forms, each based on a household appliance, which can be accessed by possessing specific appliances. The possessed appliances are based on a microwave oven (Heat Rotom), washing machine (Wash Rotom), refrigerator (Frost Rotom), electric fan (Fan Rotom), and a lawnmower (Mow Rotom). When Rotom changes form, its eyes and electric aura change colors and its aura appendages take on different shapes: red with oven mitts as Heat Rotom, blue with clothespins as Wash Rotom, purple with lightning bolts as Frost Rotom, yellow with air curls as Fan Rotom, and green with a ripped strip as Mow Rotom. According to the Rotom Catalog, Rotom in its base form is actually possessing a light bulb.
A primarily Wash Rotom in The Dex Can't Help It!, was involved in an accident caused by Ash's Pikachu that ejected it from the washing machine and getting swapped with Rotom Pokédex. Eventually, the Rotom were swapped back to their original places.
Rotom first appeared in Robust Rotom, where it caused havoc for Diamond and Pearl at the Old Chateau until Diamond understood that it only wanted to return in its plasma television and led it there. During the subsequent fight against Charon and Giratina, Rotom initially joined the battle transforming into its five forms, then left the fighting to the other legendary Pokémon only to strike at the very last, destroying Charon's device that allowed him to control every Pokémon and thus putting an end to his evil plans. After that, Rotom decided to stay with Diamond.
Bold indicates a move that gets STAB when used by Rotom
Italic indicates a move that gets STAB only when used by an evolution or alternate form of Rotom
Click on the generation numbers at the top to see Move Tutor moves from other generations
When Rotom changes into an appliance form, it learns a new move in the same way that other Pokémon may learn new moves upon evolving; if Rotom would change from one appliance form to another and knows the special move of its current form, the old special move is automatically forgotten and Rotom learns the new one. If Rotom changes to its normal form, it forgets the special move of the form it was in (if it still knows it); if the only move that Rotom knows right before reverting to its normal form is the form's special move, then that move will be replaced with Thunder Shock.
When Rotom is encountered in the Old Chateau in Diamond, Pearl, and Platinum, the music is the same as Legendary encounters, even though Rotom is not classified as one. Rotom is, to date, the only non-Legendary Pokémon to do this.
Rotom is the only Pokémon to have its type changed to a type that was not newly introduced.
No other Pokémon has the same typecombination as Rotom's base form, Heat Rotom, or Mow Rotom.
Despite becoming part Flying-type, Fan Rotom retains the Ability Levitate, being the only Flying-type Pokémon with this Ability. As its Flying type already makes it immune to Ground-type moves, its Ability is effectively useless under normal conditions.
In Inverse Battles, Fan Rotom is still protected from Ground moves due to Levitate, making it the only Flying-type Pokémon to not be affected by Ground-type moves in these battles.
All of Rotom's appliance forms except Mow Rotom are tied for or have the fewest weaknesses of all Pokémon of their secondary types.
All of Rotom's appliance forms are the lightest Pokémon of their secondary types.
Rotom is motor backwards; this may refer to the fact that motors make many appliances function, while Rotom makes them fail.
In Pokémon Platinum, an old notebook in Rotom's Room describes how a person discovered and named the first known Rotom. It appeared out of a lawn mower's motor, and the person named it Rotom due to this origin.