Gloom

 is a Grass/Poison-type Pokémon. It evolves from Oddish starting at level 21, and can evolve into Vileplume with a Leaf Stone, or into Bellossom with a Sun Stone.

Special Items
In Explorers of Time/Darkness and Sky, there are held items that work for pokemon of specific types and species. Certain items will work for all members of an evolutionary line if kept in the bag.

Type Items
Grass Poison