Well, P-Games had said it^^
I chosed the word "Uff" because if you look the broadcast on TV, the Pokemons are really really stressing when they said their own name everytime, every minute again and again.
So I said to myself "Uff what a stressing bullshit" and so "Uffi"mon was borned.

PS: My english isn't very well, I know but I hope you can understand what I mean.

MfG Kroan