The Mystery Note is a note written in Shy Guy language, found in Shy Guy's Toy Box in Paper Mario. Mario can give the note to Russ T. so he may translate it, but Mario needs to give him the Dictionary first. It is not required to translate the note in order to complete the game.
Item's game description
"Written in the language of Shy Guys, the Mystery Note gives a clue about the Toy Box."
Translation
"Hit yellow, green, red, and then blue."
Trivia
- The Shy Guy holding the Mystery Note when entering the battle has three other Shy Guys fighting alongside him. The order they appear in from left to right is the same as the translation.