Blue Key

The Blue Key is a key found in the Paper Mario series.

In Paper Mario, a Blue Key appears in Crystal Palace along with a Red Key and a Palace Key. The Blue Key is found to the south of the entrance room. After getting this key, Mario will be able to open the door in the higher place. The description reads, "A big blue key."

In Paper Mario: The Thousand-Year Door, the Blue Key is located inside the Great Tree, in the room after the small Jabbi army. The key opens the cage where ninety Punis are imprisoned, increasing Mario's Puni army from eleven to one-hundred and one. Its description reads "A key that opens the blue cell door."