Anthony's Pelipper kept Pokemon in its beak so they could use attacks during Pokemon battles that Pelipper couldn't normally learn. It was called the world's strongest Pokémon by
Anthony and he even had a sign with a picture of it so trainers would come to battle it.
It wasn't until a battle with
Ash Ketchum that things started to go wrong and the battle between
Ash's Pikachu and
Anthony's Pelipper ended in a draw. Team Rocket actually found out about his scheme and blackmailed
Anthony to cooperate with them otherwise they'd tell the world and it would stain the legend of the world's strongest Pokémon. Team Rocket then began to
Anthony's Pelipper to defeat trainers and take their Pokémon.
Anthony had a change of heart after his Pelipper was returned to his care after Team Rocket was defeated and Anthony pledged to actually raise it to be the world's strongest.