Warehouse Key

The Warehouse Key appears in Paper Mario. It opens a Warehouse in Shiver City.

When Mario must reveal who murdered Mayor of Shiver City, he found a key in frozen lake. To get it, he must Tornado Jump three times on the lake, and then dive with Sushie.

Trivia
Mario can't get the key before he see the Mayor is murdered. If he do two Tornado Jumps on the lake, he get a solid kick from Penguin Patrol.