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Mr. X's eight Robot Masters are defeated!
Now, it's time to take down Mr. X!
Now, then, if there's a Pokémon suggested that doesn't have a nickname, nickname it Mr. X and put it in the position that the Imposter ability copies from. If all five other suggestions are pre-nicknamed you can ignore this part.
Then, and this is the main suggestion, a Zoroark named Dr. Wily.