First you have to get the national dex then you have to go look into the TV, after you've beaten the Elite four.
you can see two ghosts and get a legendary,rotom. But you can only get it between 8pm and 2am. it is in the tv upstairs. you need to thump the tv and it will come out.
You see rotom at the old chateau in the eterna forest
Rotom: Old Chateau, night only
when you see people in the old chateau there ghosts look at there feet the float and disappear go to the tv room to find rotom at a certain time i think its 8pm and after
The Ghosts appear in the dining room and in the the room upstairs in the middle door the go to the room 2nd farthest to the left. You see it in the room next to you. They appear most at night
You find 152(Rotom) at the old Chateau on the second level in the second room. Hope this helps:)
Number 152 it's Rotom you can find it by talking the TV in old chateau (it has to be at night) Old Chateau is in Eterna Forest at the northwest of Floaroma town Hope i helped Source:Brain
That Pokemon is Rotom and There is only one way to actually see it and that's by battling it. You can find it in the old Chateau. Its upstairs in the room with a TV press A against it to battle it :Note: you must have the HM cut to get inside the Chateau
the old Chateu... At about 10:00pm. But it might be scary cuz there is 2 ghosts in there... A girl and a butler
Im not positive that you can get rotom before the national pokedex but in the old chateau. In one of the rooms he is in the TV
viit at night
In the Old Chateau at night, talk to the TV in the bedroom.