****ing rare truffles!

You're talking about the blue ones in KH1, right?

If so, then you just keep on hitting them in the air. Don't let them touch the ground.

If you're not talking about them, then I haven't the slightest clue what you're talking about.

 

don't use aero. use aeraga. much better

 

Just kill them, haha joking
try using a different keyblade

 

Okay, you do know what you have to do right?
They have an annoyingly high defence so you can only hit them by a certain digit. Probably one, and you have to hit them 100 times in order to deplete their whole HP Bar. Doing so gives out an item worth some munny or perhaps bragging rights (I like the sound of the second one better). Hitting them 50-99 times gives out an item of less value but still, bragging rights.
Each time you hit them, you'll also receive exp. First hit equals one exp and every other hit afterwards, the exp received increases by 1. When they hit the ground, game over.
Well that's the little facts about them

I tired the aero trick, but I failed with it, they don't bounce straight up like I was told they would, so screw that idea for now.

I got the 50-99 hits item by removing all abilities and having a weapon with long range. The End of the World place where rare truffles appear, I found that place easiest, open area, walled up and no obstacles. Just keep a X, O, X, O pattern going (plus jump towards the direction of the rare truffle), you can't combo hit them so only try hitting them once after each jump. Also Lock on to them, hitting attack while somewhat near them, Sora will automatically swing in it's direction and hit the rare truffle thus causing it to bounce higher again.

It's an annoyingly long process, and you must be pretty determined to do it. The Items aren't worth it, they do nothing but sell for some munny. Only Bragging is your real prize in my opinion, oh and a lot of exp.