You'll need to trade for a Haunter and it'll evolve.
As for trainer wise, the only one I could think of is Fantina, the Hearthome City's Gym Leader.
Trade with Pokemon Pearl or Pokemon Platinum
nobody but u can get a gastly and evovle it
the best Pokemon you can catch in Pokemon pearl is heatran
You don't find a Krookodile in Pokemon Pearl
you can not find it in pearl
in the top left corner of snowpoint city
You cannot get Genger on Pokémon Leaf Green although you can trade for it with another player. You can however get Gastly, which is Genger's pre-evolution.
you do not find dialga in Pokemon pearl
it is freakin fantina... duuuuuuuuuh!
Trade with Pokemon Pearl or Pokemon Platinum
Pokemon tower in lavender city, keep moving around and you will find one.
You need to trade for one from a friend or someone.
nobody but u can get a gastly and evovle it
the best Pokemon you can catch in Pokemon pearl is heatran
You don't find a Krookodile in Pokemon Pearl
you cant find raiku in Pokemon pearl just Pokemon gold
where do i find a totodile in Pokemon diamond/pearl on nintendods