Marie is a character from the episode "Type Casting." She and her colleague Pierre were investigating whether Sudowoodo was actually a Rock-type or Grass-type—a question that fascinated her because she believed textbook knowledge wasn't always reliable. When she observed a wild Sudowoodo using Razor Leaf and Vine Whip, moves that Rock-types shouldn't be able to learn, she felt confident calling it a Grass Pokémon.
The mystery unraveled when they noticed the Sudowoodo's fear of water, a trait totally wrong for a Grass-type. That's when they figured out it was genuinely a Rock-type all along, just using the move Mimic to copy techniques outside its own type. Marie's enthusiasm for finding Sudowoodo even inspired her grandfather, who offered a free boat ride across the river to anyone willing to catch one on his behalf.
Content compiled by AnimeList.moe from publicly available sources.