In Pokemon platinum this pokémon would be Rotom. You find him in Old Chatau in Eterna Forest.
RotomIn a TV in the old chateau
You have to see all the Pokemon in the Sinnoh Pokedex.
yes but sinnoh
150 hope i helped :) Actually there are 151 pokemon in the Sinnoh Pokedex but you only have to see 150 to get the National Pokedex.
you have to see all of the Pokemon and then you get the national pokedex from Prof. Rowen and Prof. Oak in Prof. rowen's lab after completeing the Sinnoh pokedex.
Rotom: Old Chateau, night only
yes.
You have to see every Pokemon in the sinnoh region.
Number 151 is Manaphy which you can see by looking at the book at the back of Mr.Backlots room in the Pokemon mansion south of Hearthome city. Number 152 is Rotom, which you can see by looking at the T.V in the Old Chateau between 8pm and 3:59am.
Please see the related link for a complete Pokedex from the Sinnoh region.
No, to get the National Pokedex, you only have to see every Sinnoh Pokemon. This does not include Manaphy.
You have to see every Pokemon in the Sinnoh Pokedex first and then you have to talk to Professor Rowan to get the National Pokedex.