It is needed by Mario and Vivian to guess Doopliss' name. The item can be found in the basement of the Creepy Steeple where Mario must head down the well in order to get to it. In the room with The letter "p", there is also Doopliss' pet Parrot that will reveal his name after spying on it. With both The letter "p" and Doopliss' actual name revealed, Mario can finally defeat the ghoul to get his body back.
- The letter "p" is in the same font and color as the title for Paper Mario: The Thousand-Year Door.