Boo's Sheet is an item only in Paper Mario: The Thousand-Year Door that makes Mario or a Partner Invisible for two turns. It causes enemies' attacks to miss. It can be purchased inside the Excess Express or from Charlieton. It can also be stolen from Hyper Goombas, Hyper Paragoombas, and Hyper Spiky Goombas. A Boo's Sheet can also be made by Zess T. by mixing a Point Swap and Repel Cape.
Boo's Sheets can be a great protection to characters in Peril.