Alot of people forget this item because they are to happy to get/faint palkia.
After you catch it(if you defeated it,its no use)There is a agreat item at the back.
You cannot fly out off the area so you have to go to the cave,anyway after you did catch it go all the way at the back,you will see a item called a Pearl Orb.Get that item and let palkia hold it and your good to go for the elite four(really helps)