Gastly is in there only at night with an 85% chance to find in Sprout Tower and 80% chance in Tin Tower. They are stronger in Tin Tower.
you find gastly in the Burned Tower and the Sprout Tower
In the Pokemon tower or sprout tower.
Gastly are found in sprout tower.
sprout tower
evolve gastly. you can get one from sprout tower at night.
To get Gastly you have to go to sprout tower at night.
Evolve a gastly that you can catch in the sprout tower
sprout tower or trade from older versions
Sprout Tower, the tower you find Ho-Oh in, or on certain routes in your Pokewalker.
at night in sprout tower or in route east of Violet city.
Gastly Is Common In Both Silver, and Gold. The Places There Found On Are: The Tin Tower, and The Sprout. Though They Appear More In Crystal.
You can find them in the Lost tower(South of Solacean town)and In the Old Chateau (In Eterna forest). They are mostly found at night. A Shiny gastly has a blue aura surrounding it. Gastly will evolve at lvl 25 into Haunter. and to obtain Gengar, you must trade. (btw, it is a ghost type meaning that it is useless against normal types.) Good luck trainers!