Pokémon Sapphire

The Extreme Randomizer for Pokémon Sapphire hits Hoenn's water routes especially hard — surfing encounters, fishing pools, and diving areas all spawn extreme-randomized Pokémon with reshuffled typings and moves. Sapphire's Aqua-versus-Magma conflict plays out with Pokémon whose original type-based identities are completely scrambled.

Sapphire's heavy emphasis on water routes means extreme randomization produces its biggest effects on surfing and diving areas — these encounters are already the most varied in Gen 3, and in extreme mode the Pokémon you find underwater have typings that bear no relation to their aquatic setting. Cave of Origin's climactic encounter is extreme-randomized in both typing and movepool.