Mollux, the Lamp Shell Pokemon.
Black: The toxic fluids within its shell create hypnotic colors. It is believed they change according to its mood.
White: The volatile chemical reaction that illuminates its shell requires moisture. In arid environments it runs the risk of exploding.
For the Black entry, I wanted to focus on how Mollux is indeed a lava lamp and thus work in the hypnotic colors/mood imagery. The White entry explains why this thing has "Dry Skin" as an ability. So there you go!