this is what i did, i got my crobat that new mean look and was at level 50. i went to a cave near a patch of grass. i walked in the cave, then out. checked my pokedex. and repeated. this took me a few days before i actualy found it. when i did find it i use a super repel and walked around in the grass unbtil i started to battle. i then used mean look swithsehed out my golbat for my huanter and use hypnosis. then swithced for blazekin and gt it down into minamil HP. i then used ultraballs to catch it.(it does not have to stay asleep!)
then it was mine. so do that and you will eventually find the pokemon.
sig made at THE SHOP!