How to catch cresselia without making it flee?

I have a gastly and it knows mean look but when I try to use it, cresselia flees. Help?How to catch cresselia without making it flee?
You're catching me? Me? Well, good luck! I like to break out of ultra balls!





Your Gastly is not faster than me. If he is faster, he would use Mean Look first and I can't flee. But, if you have a gastly level 1-48, I will be faster and flee all the way to a different route! So level up your Gastly and catch me if you can!How to catch cresselia without making it flee?
Get a master ball. There is no other way.
the BEST way to get it is using a





WOMBOFFET





...its ability makes the rival pokemon NOT


able to switch or runaway ...so..





GET ONE....then catch cressealia








I RECOMMEND THIS...
u can use a master ball.


if u don't have any, try puting it to sleep with a pokemon with a high speed and capture it like u would a legendary pokemon. or attack it each time u c it,(don't kill it) and when it's hp is low throw pokeballs, eventually u will get it. good luck!
thats cuz sometimes when you switch your ghastly with another pokemon the mean look wears off. or it's just is so i reccomend you use a master ball or get wobuffet with the ability shadow tag. that how made cresselia not run away
i'd use a pokemon thats strong (capable of taking hits) and knows the move mean look.
I can fight her but you have to use a mean look on her