GHASTLYS SECRET POWER TAKE 1: You know ghastly  has the attack destony bond. 
I know you can't use it first thing (duh) so instead use sleeping gas and 
then retreat him. Call out a pokemon that can beat the other pokemon and 
attack it until it wakes up then all it back and use ghastly. Then arm 
ghastly with another energy and use destony bond after that wait till the 
other pokemon attack and if it knocks out ghastly its dead. 

from your friend ChronomewZ

PS. DO NOT EVOLVE GHASTLY!