Popple is a Beanbean thief that appeared in Mario & Luigi: Superstar Saga. He is very sneaky. He is also commonly found with his sidekick, Rookie, but who Rookie is often changes. His first known Rookie was Bowser, who had gained amnesia after one of the Starshade Bros. fired him from a cannon. However, after Bowser regained his memory, Birdo became the new Rookie. After Popple was defeated again, Birdo grows angry with him. Mario and Luigi fight him for the last time, but this time he is alone. When you fight him the first time, defeating Bowser causes him to attack a few more times, then run away.
Popple is the main rival to the Wario Bros. in Mario & Luigi: Sibling Warfare. When Wario and Waluigi find a powerful gem that has a large amount of dark power in it, Popple steals the gem, thinking that it is worth millions of Coins, not knowing the danger that he and the Mushroom Kingdom are in.
Popple appears as the first enemy/boss in the game. He is encountered in the prologue robbing a bank. After his defeat he says he will be back with revenge.