Blue Key

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

In the original Paper Mario, the Blue Key opens the blue door in the Crystal Palace.

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."