Well, I'll edit my challenge into Yanma.
Walking across a nice road ,you come across a nice looking Yanma. Deciding yit looks so nice, you catch it and name it Gift, believing it is a nice gift destined to be given to you. However, really soon, you realize you have made a mistake. That nicelooking Yanma is a murderous machine. Not powerful in the slightest, but really mean. It forces its way into every double battle, and kills all his team members. The team members get daffled, and switch out after being hit by Yanma to avoid getting hit again. (So you get at least one hit in) Even then, Yanma is pittifully weak. It was born with a syndrome, and as such can only use quick attack as his sole attack. It does not understand it is weak, and believes it is the strongest attack ever. When you disagree, it continues by solo'ing at least one of every trainer owned pokemon type out there with bubble (all 17, yes including ghost, you got supersonic), which may only be a maximum of 5 levels lower than Yanma. He also has to solo Whitney with Quick Attack, because he hattes Cows and Cry baby's. After having completed these two goals, he gets overflowed with emotions and forgets his past (no evolving, Yanmega is green). Yanma can only remember using Quick Attack for all his life and you hating him for it. As such, Yanma can never use a normal type attack ever again. Actually, it does not want to use any attack at all. Instead, Yanma looks at his massive voice and his hatred towards the world and decides the only way he is going to fight is by using Supersonic. That is right, only damaging move: Supersonic. Remember: no resetting your game when Supersonic misses or fails you, deal with it. :) For every time Supersonic misses twice in a row, Yanma gets upset and steals either 20 of your most expensive pokeballs, or 10 of your most expensive items from your bag and uses Supersonic on them (equals trashing them as they scatter due to the high pitch). He is really really trying to prove his strength and finally believes the only way to do so is by solo'ing Lance by using Supersonic. Remember, no resetting, deal with it! (you might want to consider buying some revives and Elixers / Ethers)
This might even be harder, hehehehe. Oh and yes, you can get Yanma before battling Whitney.