How can I defeat a white mushroom?

Shivers = Fire spell
Spins = Aero spell
Floats in middle air = Gravity
Stops moving = Stop spell
Lays on floor = Cure spell
Circle over head = Thunder spell
Mimics: bring it on = Blizzard spell
Ps. If you want a dream weapon you should wait for it to make the same movement as the first, if you do the fire spell (for example) 3-4 times (when it shivers) you should get fire arts. When you have all the arts go see Merlin. He will notice the arts and give you the dream weapon for Donald or Goofy (Can't remember)

To "defeat" a white mushroom, you must cast the same correct spell 3 times on it, which will get you the Arts spellbooks. Here's how you can tell which spell to use:-

1) Fire - When the mushroom has it's arms crossed and is shivering
2) Blizzard - When the mushroom is fanning itself because it's hot
3) Lightning - When a light shines down on the mushroom from above
4) Cure - When the mushroom is lying on the ground in front of you (appears outside the Tent on the Deep Jungle world)
5) Gravity - When the mushroom is floating in the air (appears in Treasure Room in Agrabah)
6) Stop - When mushroom stops moving (appears in Undersea Cave in Atlantica)
7) Aero - When mushroom starts spinning around (appears on Halloween Town in the Graveyard)

If you cast 3 correct spells, but they are not the same, then the last spell you cast on the mushroom will determine what it drops. If you attack a mushroom with your Keyblade, it will count towards your White Mushrooms Defeated total in your Journal. Make sure that you Lock-On to the mushroom you want, otherwise spells like Fire will miss, or area spells like Gravity may hit other mushrooms nearby. If you find that your targeted mushroom is getting too close to another mushroom, you can reposition it by walking into it. Also, mushrooms don't stick around forever, and they waste time by looking around in wonder, so try to make several mushrooms happy at once.

If it Shivers=use Fire,Fira,Firaga
If it Fans Self=use Blizzard,Blizzara,Blizzaga
If it Grasps For your help( Lays on the ground) =use Cure,Cura,Curaga
If it Floats in mid air=use Gravity,Graviga,Gravira
If it Stops in mid motion=use Stop,Stopra,Stopga
If it Spins out of control=use Aero,Aerora,Aeroga

Also worth noting is that if you cast 3 different spells, you will get a shard of the last type of magic you cast. For instance, if you cast blizzard then cure then fire, the white mushroom will probably drop a blaze shard. A white mushroom may also drop a mystery goo, a very rare synthesis item which is an ingredient for the ultima weapon. To get mystery goo, equip lucky strike and try to cast the same spell each of the three times, which increases the odds.