sprout tower or trade from older versions
In the Pokemon tower or sprout tower.
go to the bellsprout tower at night - in the 3rd town
Yes , i have a Gastly lvl 12 ( just found it wild) and it has mean look
There are many wild Pokemon in Mt. Silver. There is also one legendary Pokemon. If you stick to the left and travel up the waterfall, you will find Moltres.
Gastly cannot be found in Pokémon X however you can find its evolved form of Haunter in Routes 14 and 19 as well as in Victory Road and Frost Cavern and then you can use Haunter and breed it with a Pokémon such as a Ditto if you have a male Haunter or if you have a female Haunter then you can also breed it with Pokémon such as Grimer, Muk, Koffing, Weezing, Misdreavus, Mismagius, Wobbuffet and then you can get a Pokémon Egg from the Daycare and it will hatch into a Gastly.
There aren't any in the wild, you'll have to trade it in from either Gold or Silver.
Shiny Pokemon appear in the wild by chance. There is about a 1 in 8,000 chance of finding a shiny Pokemon in the wild. It is just by chance and with a great amount of luck that you may find one.
To catch a shiny Gastly, there are three things you can try. First off, you can try catching a shiny Gastly in the wild. However, there is a 1 in 8192 chance of encountering a shiny Gastly and may take you hours to find one. Second, you can try breeding a shiny Gastly. There is a greater chance to find a shiny Gastly by breeding, but it still takes a few hours depending on how well you breed. Last, you can use your PokeRadar to chain Gastly. Depending on your luck and how well you chain, you can find a shiny Gastly within minutes or more. If your chain of Gastly reach up to 40 or more, your chance of finding a shiny patch is 1 in 200. A shiny patch will contain a shiny Gastly. You may even find several shiny Gastly from chaining. If you're really lucky, you can get a shiny Gastly from your first or second or even tenth chain.
you can find a wild kirlia in the Pokemon mansion area but not in the Pokemon mansion
it attracts wild Pokemon even more;)
In White forest. If it took you many days to find white forest for the first time, there will be many trainers and wild Pokemon to find. If not, then you need to invite them from someone else's black city to Your White Forest using the entralink. This should help: http://bulbapedia.bulbagarden.net/wiki/White_Forest
wild pokemon? my guess is that it's random