Lunar Stone

Lunar Stone is a stone shaped like the Moon in Paper Mario. Along with the Pyramid Stone and the Diamond Stone, Mario and his friends need this stone to gain access to Tutankoopa's tomb in the Dry Dry Ruins.

It can be found in a secret chamber, guarded by two Stone Chomps. It fits into the fifth Chomp Rock statue.

Trivia

 * In Paper Mario: The Thousand-Year Door there is a stone like this one and it's called Moon Stone