If you mean the one in the start of the long, flowery road, it dissapears, even with cheats or if you talk to it.
Anyway, it is fake.
Its proper place is at the end of the road at flower paradise.
You need Oak's Letter, recived on wi-fi, for it to appear, or cheat (not reccomended - it ruins your game).
Use a Gracedia to change its form.