Team: Glaceon, Mega-Banette, Gardevoir, Lopunny, Tsareena, and my ace: Salazzle
>Glaceon(Holding Petaya Berry)Icy Wind, Sand Attack, Natural Gift, Toxic
>Mega-BanetteOminous Wind, Gunk Shot, Foul Play, Toxic
>GardevoirHidden Power Poison, Focus Blast, Misty Terrain, Toxic
>Lopunny(Holding Petaya Berry)Secret Power, Attract, Natural Gift, Toxic
>TsareenaAromatic Mist, Seed Bomb, Play Rough, Toxic
>Salazzle(Holding Poisonium Z)Poison Gas, Venoshock, Sweet Scent, Foul Play
My Gym is a baked beans factory full of gassy female trainers, you won't be able to enter it at first because you'll need to attain the move "Defog" since the area surrounding the gym is covered in a thick stinky yellowish-brown poisonous fog, and you need to clear it out before you can enter.
The gym puzzle will involve turning on the ventilation system by doing a squencer tile puzzle (like the one in Knights of the Old Republic) for each room to clear up the stinky poison fog blocking your path to the door to the next room, which you repeat until you reach me. When you defeat me i'll give out a TM for Poison Gas.
And this would be my battle theme:
https://www.youtube.com/watch?v=qG2HwH1JkAIPic related is a crude representation of what my gym would look like.