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I think it'd be interesting to do this by Gen. What ruled gen 1, 2, etc...and easier to specify. I don't think we can dispute Curselax as the top of gen 2, or crocune for gen 3, for example.
Final Submission
Mollux, the Disco Pokemon
Black: Humans that have spent too much time around NECTURNA or PYROAK are often unduly fascinated with the glow from MOLLUX's lamp.
White: Decades ago, human interest in the glow from MOLLUX lamp drove the species nearly to extinction. Pokemon...