Im talking about gen 4 and I know you can change rotom forms in one of the D/P/Pt games and Hg/SS. But once you change its forms to lets say the heat one which is fire/electric typing. Then does it get stab on ghost attacks at all? And can you change its forms back to the original one once you've changed it? Also is it kind of like an arceus where you can just change the forms depending on your mood I really dont understand how the forms work and I looked it up on google but I still dont understand it so can someone explain this to me in an easy way so I can understand?
>In Generation IV, it was Electric/Ghost regardless of its form.
Source: Bulbapedia
Yes, you change him back to his original form.
It's only in Generation V that his type changes with his form.
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 a rotary fan it becomes Fan Rotom, and is Electric/Flying
When it possesses a lawn mower it becomes Mow Rotom, and is Electric/Grass