From the Super Mario Wiki, the Mario encyclopedia
Boddle's assistant is a Beanish character that assists Boddle with the Yoshi Theater in Mario & Luigi: Superstar Saga and the remake, Mario & Luigi: Superstar Saga + Bowser's Minions. He appears with blonde hair and a blue shirt in the original game; unused sprites of the assistant found in the code show him with brown hair and a purple shirt (shown below), which is the palette used for him in the remake.
Boddle's assistant is very loyal to Boddle, to the point that he takes an uppity tone with Mario and Luigi when they explain to him that they want the Beanstar piece Boddle was planning to use for the entrance sign of the theater. The assistant tries to shoo them off, believing them to be swindlers out to rob Boddle of his money again, and begs Boddle not to listen. Boddle hits him for his rudeness (using his costume and a Yoshi's Island-style targeting cursor) before explaining that he will trade the Beanstar piece if the Bros. can find a replacement, despite the assistant protesting (which earns him another hit from Boddle). Boddle's assistant then mentions the Neon Eggs, which Boddle states he will accept in exchange for his Beanstar piece; the assistant claims that the Mario Bros. could never retrieve them, causing Boddle to hit him yet again.
Once Boddle explains his reasoning and agrees to the trade, Boddle's assistant fawns over his generosity (despite trying to interfere with it earlier) and demands Mario and Luigi thank him before hurrying them to find the Neon Eggs. Once the duo retrieve all seven and Boddle places them on the sign, he rewards the Bros. with the Beanstar piece before he and his assistant head into the theater to prepare for the grand opening.