Battle Frontier (Generation III)

The Battle Frontier is a whole new area introduced in Pokemon Emerald which features several areas where you can battle your pokémon.

Battle Pike (formerly Battle Tube)

This area is a giant Seviper. With each round, you face a set of three rooms. One could contain a battle, one may inflict a status on your pokémon, it could be full of wild pokémon. These are some of the encounters.