What is the only Generation III Pokemon whose name begins with the letter I?

The only Generation III Pokémon whose name begins with the letter "I" is Illumise. Illumise is a Bug type Pokémon with a pink and blue colored body. It is known for its ability to emit a sweet fragrance from its antennae, which attracts and mesmerizes other Pokémon. Illumise can be commonly found in forests and meadows, often appearing together with its counterpart, Volbeat.