Ninja Boy (Trainer class)
From Bulbapedia, the community-driven Pokémon encyclopedia.
A Ninja Boy is a type of Pokémon trainer that first debuted in the Generation III games. They appear as little boys dressed as ninjas. They conceal themselves in the landscape and ambush passing trainers.
They specialize in a combination of Poison-type Pokémon and evolutions of Nincada.