Little Mouser (character)
From the Super Mario Wiki
Little Mouser is a character in Paper Mario. An inhabitant of Dry Dry Desert, Little Mouser is a Nomadimouse and the owner of Little Mouser's Shop. He is also a member of Moustafa's unnamed organization. He is purple, and as such resembles Little Mousers' original artwork.
When Mario and his partners enter Dry Dry Outpost in Chapter 2, Little Mouser can be seen temporarily closing his shop and running quickly to Sheek, or Moustafa in disguise. When approached, he rushes back to his shop and re-open it. Mario needs to buy first a Dried Shroom and then a Dusty Hammer to show his "membership" of Moustafa's group. After this, Little Mouser tells him to go to the highest point in Dry Dry Outpost to find Moustafa.
Later in the game, Little Mouser is involved in two sidequests: letter delivery and Koopa Koot's favor. One long chain of letter delivery with Parakarry involves delivering a letter from Miss T. to Little Mouser. After receiving it, Little Mouser will reveal it is an order for various beauty products and that Miss T. is one of his best customers. Little Mouser then asks them to deliver his letter to Franky in Boo's Mansion. Additionally, one of Koopa Koot's favors involves obtaining a Red Jar from Little Mouser, who will give Mario the artifact if he purchases a Dusty Hammer, some Dried Pasta, another Dusty Hammer and a Dried Shroom, in that order, from his shop.