From the Super Mario Wiki
When the player decides to stop here, they will meet Lakitu, a Toad Force V fan who cannot remember a certain quote from episode 28. His quest, What's That Line?, involves getting someone in town for the quote. Go to the 1st floor of Mushroom Condo and talk to Mushbert, who will recite the line. If the player returns to Lakitu and tells him the line, he'll reward them with the Gaddget, Bait 'n Wait.