Field Type: Electric/Rock
Complexity: Simple/Moderate
Restrictions: Water source far below (costing extra energy to use), seismic activity will cause crystals to drop, electric and rock moves get +2 BAP, no weather.
This is a colosseum from Pokemon Battle Revolution. It is an underground cave with crystals glowing with electricity (or at least that is how I perceive it). There is a nicely painted arena-rectangle for battling, but that certainly doesn't define any boundaries. This cave is just charged with electricity and full of rock. All electric or rock moves get +3 to their base attack power. There is no water supply except for down below, so it takes extra energy (3 energy) to summon it up for moves like Surf. If any seismic activity should take place, all Pokemon are hit will crystals (a 4 BAP physical electric attack with 3 Attack). Since it is an underground cave, no weather can reach the arena. It should make for interesting battles - it could potentially even be a gym if someone wanted to use it for that!